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Multilateral peace operations in Afghanistan between 2001 and 2021

Multilateral peace operations in Afghanistan between 2001 and 2021
ISAF troops. Photo: Flickr/Combat Camera Poland

Four multilateral peace operations were deployed in Afghanistan during the 20 years between the start of the United States-led intervention that toppled the Taliban government in the country in 2001 and the withdrawal of US and allied troops this year. One of them, the International Security Assistance Force (ISAF), was the largest multilateral peace operation ever deployed, and was also the first peace operation mounted by the North Atlantic Treaty Organization (NATO) outside Europe. ISAF functioned in parallel to Operation Enduring Freedom, a counter-terrorism operation in Afghanistan led by the USA from 2001 to 2014.

This SIPRI Topical Backgrounder gives an overview of the four multilateral peace operations that were active in Afghanistan between 2001 and 2021: ISAF and the Resolute Support Mission (RSM), along with the much smaller United Nations Assistance Mission in Afghanistan (UNAMA) and the European Union Police Mission in Afghanistan (EUPOL Afghanistan).

It presents SIPRI data on the number and categories of international personnel deployed in each operation, drawn from the SIPRI Multilateral Peace Operations Database. Note that all references to personnel deployments relate only to international personnel and exclude contractors. Unless otherwise indicated, the annual personnel figures given are for personnel deployed in-country as of 31 December. For more information see the database methods and definitions page.

The International Security Assistance Force and the Resolute Support Mission

Personnel numbers

ISAF was authorized by the United Nations Security Council in December 2001. As a multinational ad hoc operation with rotating command, ISAF’s initial mandate was to help the Afghan Interim Authority, the administration established in December 2001 following UN-brokered talks in Bonn, Germany, to maintain security in Kabul and its surrounding areas. Within a year after ISAF was launched, it numbered almost 5000 personnel (see figure 1).

In August 2003, at the request of the then-renamed Afghan Transitional Authority, NATO took command of ISAF. In October of that year, UN Security Council Resolution 1510 expanded ISAF’s mandate to cover the whole of Afghanistan ‘as resources permit’, providing security support for ‘reconstruction and humanitarian efforts’ and ‘the performance of other tasks in support of the Bonn Agreement’.

Over the next four years, the number of military personnel deployed by ISAF grew consistently, reaching around 9000 in 2005. A year later, ISAF’s presence covered the whole country and the operation had over 30 000 troops on the ground.

With the expansion of ISAF to the eastern and southern regions of Afghanistan, its troops became increasingly involved in fighting an insurgency. In response, ISAF launched a new counterinsurgency strategy in 2009 and US President Barack Obama ordered a ‘surge of some 30 000 additional US troops. ISAF troop numbers continued to grow during 2010, peaking at more than 130 000.

From 2012, NATO started the transition of security responsibilities to the Afghan National Security Forces. This process culminated in the closure of ISAF at the end of 2014.

At the beginning of 2015, at the invitation of the Afghan government and in accordance with UN Security Council Resolution 2189, NATO opened a follow-on operation to ISAF, the RSM. The objective of this non-combat operation was to train, advise and assist the Afghan security forces and institutions to develop their capacities. RSM deployments numbered around 15 000–17 000 military personnel until its drawdown started in 2020. The RSM started the final withdrawal of its troops in May 2021, and was terminated in early September 2021.


Contributing countries

From 2001 to 2008, the majority of ISAF military personnel came from the European Union (EU) member states (see figure 1). Only from 2006 did the USA became a significant troop contributor. However, when ISAF adopted its new counterinsurgency strategy in 2009, most of the new troops came from the USA. In 2011, the USA provided approximately 70 per cent of all ISAF military deployments. EU member states contributed another 25 per cent and other countries around 5 per cent.

Both European and US troop deployments to ISAF started to decrease from 2011. The USAs troop contribution fell from 38 000 in December 2013 to 5500 at the closure of ISAF in December 2014. In the same period, EU members states’ troop deployments fell from approximately 15 000 to 5000.

Shortly after the start of the RSM, US deployment numbers increased slightly again to 6800 and continued to grow until 2019, when they reached 8000 troops. Deployments from EU members states, although smaller than those from the USA, increased roughly in parallel.

In an agreement with the Taliban signed in February 2020, the USA committed to withdraw all its forces from Afghanistan by May 2021. At the end of 2020, EU member states and the United Kingdom once again accounted for more military personnel under NATO command in Afghanistan than the USA, for the first time since 2008.

The United Nations Assistance Mission in Afghanistan

The UN Security Council established UNAMA in March 2002 to ‘integrate all the existing United Nations elements in Afghanistan into a single mission’. It is currently the only remaining multilateral peace operation in the country, with a UN Security Council mandate until 17 September 2021. Although UNAMA’s mandate has been renewed and updated annually, its core mandate—namely the provision of good offices, human rights monitoring, the protection of civilians, and the promotion of good governance and regional cooperation—has remained unaltered.

UNAMA primarily deploys civilian personnel, although it has also included a small number of military and police personnel throughout (see figure 2). Civilian personnel numbers have ranged between 217 and 427, peaking in 2011. The number of military personnel on the ground has varied between 1 and 23, while the number of police personnel has varied between 1 and 8. Since 2013, UNAMA’s personnel numbers have consistently declined.


The European Union Police Mission in Afghanistan

In May 2007 the Council of the EU established EUPOL Afghanistan as a civilian mission under the Common Security and Defence Policy (CSDP), with the objective of supporting the Afghan government’s efforts to build a police force capable of operating throughout the country. The mission was primarily composed of law-enforcement and rule-of-law experts seconded by EU member states.

EU member states initially authorized the deployment of 200 personnel in the mission. In 2008, EU member states agreed to double the authorized number of personnel to 400. Despite this, and rapid growth in deployments at the end of 2008, EUPOL Afghanistan only reached 200 personnel in February 2009 (see figure 3).

In fact, the number of international personnel deployed by EUPOL Afghanistan never reached 400, peaking at 353 personnel in 2012. EUPOL Afghanistan closed in 2016. This disengagement was largely synchronized with ISAF’s drawdown, due to concerns about security in the absence of ISAF forces.



Despite calls by some peacekeeping experts for the deployment of a new UN observer mission to Afghanistan, it is highly unlikely that either the UN Security Council or the new Taliban government will agree to such a proposal. Therefore, with the closure of the RSM the deployment of military personnel in multilateral peace operations in Afghanistan came to an end. The future of UNAMA and whether its mandate will be renewed largely depend on how the UN Security Council views the current security situation in Afghanistan and the willingness of the Taliban government to cooperate and with the UN.

The wider implications for multilateral peace operations of the return of the Taliban to power in Afghanistan may look significant at first sight. However, the result did not come as a complete surprise. French President Emanuel Macron, for example, drew the comparison when discussing Mali: ‘I don't believe in “state-building” . . . We already drew that lesson for Mali before what happened in Afghanistan’. Indeed, the UN Security Council has already apparently lost its appetite for setting up large-scale UN peacekeeping operations since the establishment of the UN Multidimensional Integrated Stabilization Mission in the Central African Republic in 2014. As a consequence, while the number of multilateral peace operations has remained relatively stable since 2014, the numbers of personnel deployed in them has decreased from about 160 000 to some 127 000 at the end of 2020.


Dr Claudia Pfeifer Cruz is a Researcher in the SIPRI Peace Operations and Conflict Management Programme.
Dr Jaïr van der Lijn is a Senior Researcher and Director of the SIPRI Peace Operations and Conflict Management Programme.