War on terror

The war on terror was a big, global military effort started by the United States after the September 11 attacks in 2001. It was officially called the Global War on Terrorism and aimed to stop groups that use violence against innocent people. The main focus was on stopping groups like al-Qaeda and the Taliban, as well as stopping other dangerous groups and leaders who supported such actions.

This effort led to many military actions in different places, such as Afghanistan, Iraq, and other countries. It changed how countries worked together to keep people safe and brought up many questions about right and wrong ways to fight danger. Over time, people had different opinions about whether these actions helped or hurt the world.

Today, the ideas from this time still shape how countries try to protect their people and work together to prevent violence. It showed how important it is to think carefully about how we keep people safe while also respecting everyone's rights.

Etymology

The phrase war on terror was used to describe a big military effort led by the United States, the United Kingdom, and some other countries. They were fighting against groups and leaders they called terrorists. This wasn’t the only name for the fight—it was also called "World War III", "World War IV", "Bush’s War on Terror", "The Long War", "The Forever War", "The Global War on Terror", "The War Against al-Qaeda", or "The War of Terror".

Before the attacks on September 11, 2001, people sometimes talked about fighting terrorism, but after that day, the phrase became very well-known. Leaders said this was a big fight that would take time. Over the years, some leaders stopped using the phrase "war on terror" and instead talked about working against specific groups that threaten safety. Even so, the idea of fighting against these groups continued in different forms.

Background

See also: Islamic terrorism and List of Islamist terrorist attacks

In the late 1990s, a group led by Osama bin Laden began planning attacks against the United States from Afghanistan, where a strict government called the Taliban was in control. Bin Laden openly called for war against the United States and the West.

These plans led to several attacks, including bombings of U.S. embassies in Kenya and Tanzania in 1998, and an attack on a U.S. ship in Yemen in 2000. The most tragic of these was the attacks on September 11, 2001, when nineteen men took control of four airplanes. They crashed two into buildings in New York City, one into a building in Virginia, and the fourth into a field in Pennsylvania after some passengers tried to stop them. Many people were hurt or lost their lives that day.

Main article: September 11 attacks

American objectives

The Authorization for Use of Military Force Against Terrorists was made law in September 2001 to allow the United States to use its military against groups or countries linked to the September 11 attacks. It gave the president the power to take action against anyone who helped plan, support, or carry out these attacks.

The goals of this effort included stopping harmful groups, stopping countries from supporting them, reducing conditions that might lead to such actions, and protecting American people and interests both at home and around the world. The law allowed military actions in many countries, sometimes without full public details.

Timeline

For a chronological guide, see timeline of the War on Terror.

The War on Terror began after attacks in 2001, when the United States started a global effort to stop harmful groups. This effort focused on stopping groups that used violence, like those involved in the attacks. It was a big change from the time when the world was mostly focused on a different kind of conflict.

Operation Enduring Freedom

Main article: Operation Enduring Freedom

Operation Enduring Freedom was the name used for a big military effort started by the United States after the attacks on September 11, 2001. This effort, part of a larger fight against groups that use violence, focused mainly on a group called al-Qaeda and their allies. At first, the operation was called "Eternal Justice," but it was changed to "Enduring Freedom" because the original name caused upset feelings in many parts of the world.

Afghanistan

Main article: War in Afghanistan (2001–2021)

See also: List of military operations in the war in Afghanistan (2001–2021)

After the September 11 attacks, the leader of the United States asked the leaders of Afghanistan to give up important members of al-Qaeda or face attacks. When they did not agree, the United States and its friends started a military operation in Afghanistan. This began with airplanes dropping bombs on places where these groups were hiding. Later, soldiers moved into the country to fight against these groups. Over time, the fighting continued in many parts of Afghanistan as these groups tried to come back.

In 2014, Afghanistan and the United States agreed that American and NATO soldiers could stay in the country to help until at least 2024. But in 2020, the United States made a deal with these leaders to start bringing soldiers home. By 2021, most soldiers had left, and the leaders took control of the country again.

International Security Assistance Force

Main article: International Security Assistance Force

After the fighting began, a group called the International Security Assistance Force was created to help the new government in Afghanistan. This group included soldiers from many countries working together to support peace and order.

Philippines

Main article: Operation Enduring Freedom – Philippines

In 2002, the United States sent soldiers to the Philippines to help local forces fight against some harmful groups. They also worked on projects to help people in the area, like giving medical care, as part of efforts to gain trust and support from local communities.

Trans-Sahara (Northern Africa)

Main article: Operation Juniper Shield

The United States and its partners also worked in parts of Africa to stop harmful groups and to prevent the illegal trade of weapons and drugs. This included helping countries like Mali when they asked for support against groups that wanted to control parts of their land.

Horn of Africa and the Red Sea

Main article: Operation Enduring Freedom – Horn of Africa

Further information: Ethiopian occupation of Somalia (2006–2009), Somali Civil War (2009–present), American military intervention in Somalia (2007–present), and CIA activities in Somalia

The United States also worked in the Horn of Africa to stop harmful activities and to train local soldiers. This included helping countries like Djibouti, Kenya, and Ethiopia. The effort also involved giving aid, like building schools and clinics, to support the communities where they worked.

Military operations by country

Iraq War

Main article: Iraq War

Further information: Iraq War and the war on terror

2002 State of the Union Address

Main article: Axis of evil

During a speech in 2002, a leader of the United States talked about three countries — North Korea, Iran, and Iraq — saying they were helping dangerous groups and trying to make weapons that could harm many people. These countries were called the "Axis of evil".

Prelude

Further information: Preparations for 2003 invasion of Iraq and Saddam–al-Qaeda conspiracy theory

In 2002, the United States asked for permission to use military force against Iraq. In early 2003, a leader spoke at the United Nations, saying Iraq had secret weapons and connections with a group called Al-Qaeda.

Invasion of Iraq

Main article: 2003 invasion of Iraq

The Iraq War started in March 2003 with airplanes and soldiers from the United States and its friends. They said Iraq had weapons of mass destruction, but later this was found to be wrong. Iraq had been listed as helping dangerous groups since 1990. The fighting began with a battle at a port town, and soon the capital, Baghdad, was taken over. By May 2003, the main fighting stopped.

Iraqi Insurgency (2003–11)

Main article: Iraqi Insurgency

After the fighting stopped, some people in Iraq started fighting back against the United States and the new government. These fighters included members who used to work for the old leader, Saddam Hussein, and others who wanted to create an old Islamic state. Saddam Hussein was caught in 2003 and removed from power in 2006.

In 2007, a new plan was tried that helped lower fighting in Iraq. The United States stopped most big fighting there in 2010.

War in Iraq (2013–17)

Main article: War in Iraq (2013–2017)

After most United States soldiers left in 2011, some came back in 2014 to help fight a group called the Islamic State. As of July 2021, about 2,500 United States soldiers were still in Iraq, helping to fight the rest of this group.

Pakistan

Main articles: Pakistan in the war on terror, Insurgency in Khyber Pakhtunkhwa, and Pakistan and state-sponsored terrorism

See also: Drone strikes in Pakistan, List of drone strikes in Pakistan, Killing of Osama bin Laden, and Pakistan–United States relations

After the attacks on September 11, 2001, the leader of Pakistan agreed to help the United States. This led to the United States using air bases in Pakistan. In 2002, the leader of Pakistan spoke out against extreme groups and arrested some leaders of these groups.

In 2004, the army of Pakistan started operations in areas where extreme groups were hiding. The United States used drone airplanes to attack these groups in Pakistan, which caused some disagreement about rules and agreements.

Yemen

Main articles: Al-Qaeda insurgency in Yemen, Drone strikes in Yemen, and Yemeni civil war (2014-present)

The United States has used military actions against extreme groups in Yemen since the war on terror began. Yemen has a weak government, and extreme groups have found places to hide and plan. The United States has given more help and money to Yemen to support efforts against these groups.

Current phase: Islamic State, Iran, and focus on narcoterrorism (2021–present)

Main articles: US intervention in the Syrian civil war § 2024–present: Post-Assad drawdown, Operation Hawkeye Strike, 2025 United States strikes in Nigeria, War on drugs § War on cartels (2025–present), and Operation Southern Spear

During the 2020s, the efforts to stop harmful groups grew smaller and less intense after the end of big wars in Iraq and Afghanistan. The United States and its partners now focus on smarter ways to protect people, like using information and working together with friends. In 2022, a leader of a harmful group was removed by a drone, ending a long time of strong leadership.

Today, there are still operations in places like Somalia and Yemen. Some groups continue to cause trouble by using the internet to share messages and plan activities. In recent years, there have been some fights between countries, and in 2025, the United States took steps to stop groups linked to illegal activities in Latin America. These actions show how the way to protect people is changing, with more focus on working together and using different methods to keep everyone safe.

Other military operations

Operation Inherent Resolve (Syria and Iraq)

Main articles: Operation Inherent Resolve, Military intervention against ISIL, and List of wars and battles involving ISIL

Further information: American-led intervention in Iraq (2014–2021), Spillover of the Syrian Civil War, and American-led intervention in Syria

In 2014, the United States began using airstrikes to fight a group called the Islamic State in Iraq and Syria. The goal was to weaken and eventually defeat this group. More troops were sent to help local forces, and attacks continued in both Iraq and Syria.

Islamic State of Lanao and the Battle of Marawi

With the rise of the Islamic State in Iraq and Syria, smaller groups inspired by them appeared in other parts of the world, including the Philippines. One such group attacked the city of Marawi in 2017, leading to a long and difficult battle.

Libyan War

Main articles: Factional violence in Libya (2011–2014), Libyan Civil War (2014–2020), and American intervention in Libya (2015–2019)

The Islamic State also tried to gain control in Libya, taking over parts of the country. Local forces, with help from airstrikes, fought back and eventually pushed them out of their main city, Sirte.

American military intervention in Cameroon

In 2015, the United States sent soldiers to Cameroon to help local forces fight the Islamic State. Their role was to support and provide information, not to fight directly.

Operation Active Endeavour

Main article: Operation Active Endeavour

After the attacks on September 11, 2001, NATO began a naval operation called Active Endeavour. Its purpose was to keep the seas safe by stopping any movement of harmful groups or weapons.

Fighting in Kashmir

Main article: Kashmir conflict

Some groups in Kashmir have been involved in conflicts, and there have been concerns about links to larger militant networks. There have been several incidents involving drone attacks and military operations in the region.

Anti-terror campaigns by other powers

As part of ongoing regional conflicts, countries like Israel and Saudi Arabia have taken actions against militant groups. Colombia has also focused on counter-terrorism efforts, especially during the presidency of Álvaro Uribe. In recent years, China has conducted campaigns against separatist movements in Xinjiang, and Russia has dealt with separatist and militant groups in Chechnya and during its involvement in the Syrian Civil War.

International military support

Main articles: Participants in Operation Enduring Freedom and Multi-National Force – Iraq

See also: Coalition combat operations in Afghanistan in 2008 and Afghan War order of battle 2012

The invasion of Afghanistan was the first major action in this global effort, with forces from the United States, the United Kingdom, and the Afghan Northern Alliance. Later, troops and aircraft from countries such as Australia, Canada, Denmark, France, Italy, the Netherlands, New Zealand, and Norway joined in. By 2006, around 33,000 troops were in Afghanistan.

After the attacks on September 11, 2001, NATO declared that these attacks were an attack on all its members. Australia also promised support. In the months that followed, NATO worked together to protect people and keep travel safe. This included naval operations in the Mediterranean Sea to stop dangerous groups and to make sure ships could travel safely.

Domestic aspects

Main article: Patriot Act

Further information: Mass surveillance in the United States and NSPM-7

After the attacks on September 11, 2001, the United States made changes to better protect its people. New groups were formed to help keep the country safe, like the United States Department of Homeland Security. Laws were also changed to help police and government workers find people who might plan bad actions.

These changes sometimes made people worry about their rights. Some believed the new rules went too far and took away freedoms that people normally have. Courts looked at these concerns to make sure everything followed the rules of the country.

Extrajudicial detention

After the September 11 attacks in 2001, the United States started a program called "extraordinary rendition." This meant taking people from one country to another without following normal laws. The goal was to question these individuals in places where they could be held without the usual legal protections. This practice continued even after new leaders took over in the United States.

The United States also used secret prisons, known as "black sites," to hold people captured during their efforts against harmful groups. These secret prisons were not officially admitted to by the United States government. Holding people in these secret places went against international agreements that many countries, including those in Europe, had agreed to follow. Some of these secret prisons were later closed, but the actions caused problems and debates in many countries.

The United States also opened a prison at Guantanamo Bay in 2002. This prison was set up in a special area that is not part of the United States, which allowed the government to avoid some normal rules. Many people were kept there for a long time without being charged with a crime. Some were eventually sent to other countries. As of 2025, only a few people remain in this prison, with some waiting to be moved, some facing charges, and others being held without a set end date.

Main article: Guantanamo Bay detention camp

Major terrorist attacks and plots since 9/11

Following the start of efforts to stop harmful groups after the attacks on September 11, 2001, several groups and individuals have carried out attacks in many places, including countries where fighting was not happening.

Attacks by Al-Qaeda

Main articles: al-Qaeda and Timeline of al-Qaeda attacks

• The 2002 Bali bombings in Indonesia were done by members of Jemaah Islamiyah, a group linked to Al-Qaeda.
• Al-Qaeda in the Islamic Maghreb said they were responsible for the 11 April 2007 Algiers bombings, targeting government offices.
• Morocco said Al-Qaeda was to blame for the 2011 Marrakech bombing, though the group denied this.
• No one claimed responsibility for the 2012 US Consulate attack in Benghazi in Libya. Some believe groups linked to Al-Qaeda may have been involved.
• The people in the Charlie Hebdo shooting in Paris said they were part of al-Qaeda’s Al-Qaeda in the Arabian Peninsula.
• Al-Qaeda in the Arabian Peninsula said they were behind the Naval Air Station Pensacola shooting in the United States.

Islamic State

Main articles: Islamic State of Iraq and the Levant and List of terrorist incidents linked to ISIL

See also: List of wars and battles involving ISIL

• The 2013 Reyhanlı bombings in Turkey caused many injuries.
• The 2014 Canadian parliament shootings were inspired by Islamic State and resulted in the death of a soldier.
• The November 2015 Paris attacks caused many deaths and injuries, and Islamic State said they were responsible.
• The 2015 San Bernardino attack in California killed many people.
• The 2016 Brussels bombings in Belgium caused many deaths and injuries.
• The 2016 Orlando nightclub shooting in Florida was one of the worst such events in U.S. history.
• The 2024 Crocus City Hall attack in Russia was one of the deadliest attacks in recent history.

Attacks by other Islamist militant groups and individuals

• The 2003 Casablanca bombings were carried out by Salafia Jihadia.
• The 2003 Istanbul bombings targeted British and Jewish sites.
• The 2004 Madrid train bombings were done by people opposing Spain’s involvement in wars abroad.
• The 7 July 2005 London bombings targeted London’s public transport.
• The 2007 Glasgow International Airport attack was carried out by two individuals.
• The 2023 7th October Attack targeted Israeli soldiers and civilians and was one of the deadliest attacks in Israel’s history.

Alleged plots and unsuccessful attacks

There have been reports of planned attacks that did not succeed, including:

• 2001 threat against West Coast suspension bridges (United States)
• 2004 financial buildings plot (The United States and the United Kingdom)
• 21 July 2005 London bombings (United Kingdom)
• 2006 Toronto terrorism plot (Canada)
• 2006 transatlantic aircraft plot involving liquids on airplanes
• 2006 Hudson River bomb plot (United States)
• 2007 Fort Dix attack plot (United States)
• 2007 London car bombs (United Kingdom)
• 2007 John F. Kennedy International Airport attack plot (United States)
• 2009 Bronx terrorism plot (United States)
• 2009 New York City Subway and United Kingdom plot (The United States and the United Kingdom)
• 2009 Northwest Airlines Flight 253 bombing plot (United States)
• 2010 Stockholm bombings (Sweden)
• 2010 Times Square car bombing attempt (United States)
• 2010 cargo plane bomb plot (United States)
• 2010 Portland car bomb plot (United States)
• 2011 Manhattan terrorism plot (United States)
• 2013 Via Rail Canada terrorism plot (Canada)
• 2014 mass-beheading plot (Australia)

Casualties

The war on terror, also called the Global War on Terrorism, began after the September 11 attacks in 2001. It involved many countries and focused on stopping groups that used violence.

It is hard to know exactly how many people were hurt or died because the fighting happened in many places. Some reports say that between 500,000 and 900,000 people may have been hurt or died in places like Iraq, Afghanistan, and Syria. Many more people were forced to leave their homes because of the fighting. In the United States, more than 200,000 veterans have needed help for mental health after their time in these wars.

Costs

The war on terror lasted for many years and cost a lot of money — much more than people first thought. Experts say the total cost was around $8 trillion for operations from 2001 to 2022, plus another $2.2 trillion for helping veterans over the next 30 years. This money was spent in places like Afghanistan, Iraq, and Syria, as well as other areas.

Every day, the government was spending millions to support military operations. For example, in 2015, it was estimated that the United States spent about $9.4 million each day on efforts in Syria and Iraq. The costs kept growing over time, showing how expensive and long this conflict was.

Criticism

Main article: Criticism of the war on terror

See also: United States war crimes § War on Terror

Many people have questioned the ideas and actions behind the global effort against terrorism that began after the September 11 attacks. Some say calling it a "war" is not right because terrorism is a method used by people, not a country or group you can fight like in other wars. They worry that this way of thinking has been used to limit people’s freedoms and treat others unfairly.

Others point out that using military force in places like Iraq and Afghanistan has caused many problems, including hurting many people who were not involved in fighting. Some believe that this approach has made some countries less trusted around the world. There are also concerns that the effort has sometimes been used to control groups of people inside countries or to support actions that are not fair. Overall, many think the effort against terrorism has had big effects on many lives and costs a lot of money.