Kosovo War

The Kosovo War, fought from 28 February 1998 to 11 June 1999, was a major conflict in the Balkans between the Federal Republic of Yugoslavia—comprising Serbia and Montenegro—and the ethnic Albanian insurgent movement known as the Kosovo Liberation Army (KLA). The war escalated into an international crisis when NATO intervened with an air campaign against Yugoslav military targets, ultimately forcing the withdrawal of Yugoslav forces from Kosovo. The conflict was the culmination of decades of tension between Kosovo Albanians and Serbian authorities and remains one of the most consequential European conflicts of the late twentieth century.

Background to the Conflict

Tensions between Albanians and Serbs in Kosovo have deep historical roots. In the late nineteenth century, Albanian communities were displaced from territories annexed by the Principality of Serbia, contributing to cycles of retaliation. During the Balkan Wars (1912–1913), widespread atrocities were committed, including massacres of Albanians by Serbian forces. After the First World War, Kosovo became part of the Serb-dominated Kingdom of Yugoslavia despite demands from many Albanians for union with Albania.
Between the world wars and again after 1945, Yugoslav authorities pursued policies that curtailed Albanian political expression and promoted the settlement of Serbian and Montenegrin colonists, prompting further resentment. During the Axis occupation (1941–1945), some Albanian collaborators persecuted Serb settlers, and after the war the new socialist government of Yugoslavia barred the return of many displaced Serbs.
Under Josip Broz Tito, Kosovo was designated an autonomous province within the Socialist Republic of Serbia. Autonomy reduced direct Serbian control but did not end ethnic tension. By the 1980s, deteriorating economic conditions and rising nationalism intensified Albanian demands for republican status and Serbian concerns about political stability. In 1989, Slobodan Milošević revoked much of Kosovo’s autonomy, placing the province under firm Serbian control. Albanian schools and institutions faced restrictions, and widespread discrimination fuelled public discontent.

Rise of the Kosovo Liberation Army

Throughout the early 1990s Kosovo Albanian leaders, led by Ibrahim Rugova, pursued a strategy of peaceful resistance. However, Kosovo’s exclusion from the Dayton Agreement (1995), which settled the Bosnian conflict, convinced many that non-violence had failed to bring Kosovo to international attention.
The KLA, formed earlier in the decade, intensified armed operations from 1995 onwards. In 1996, it claimed responsibility for sabotage and attacks on police stations. A major influx of weapons followed the Albanian rebellion of 1997, enabling the KLA to expand recruitment and operations. By early 1998, clashes between the KLA and Yugoslav security forces escalated sharply. Serbian police and paramilitary units began large-scale reprisals, targeting KLA sympathisers and political opponents. Hundreds of civilians were killed, and by March 1999 over 370,000 Kosovo Albanians were displaced.

International Efforts and Failure of the Rambouillet Talks

Growing violence prompted international monitoring. The OSCE Kosovo Verification Mission (KVM) attempted to stabilise conditions but withdrew in March 1999 as Yugoslav forces launched a major campaign of repression. The Rambouillet negotiations, intended to secure an autonomy framework, collapsed when Yugoslavia rejected provisions allowing NATO peacekeepers free movement within the country.

NATO Intervention and the Air Campaign

On 24 March 1999, NATO launched an aerial bombing campaign against Yugoslav targets without United Nations Security Council approval, citing humanitarian grounds. The campaign sought to halt attacks on civilians and compel the withdrawal of Yugoslav forces from Kosovo.
The air strikes damaged military infrastructure, transport networks, and government facilities, including the Yugoslav Ministry of Defence in Belgrade. Civilian casualties from NATO strikes are estimated between 489 and 528 according to Human Rights Watch, or 454 according to the Humanitarian Law Center. Among the dead were three Chinese journalists killed when NATO mistakenly bombed the Chinese embassy in Belgrade.
Meanwhile, Yugoslav forces continued mass expulsions and assaults on Kosovo Albanian communities. Reports document killings, arson, rape, and systematic intimidation, forcing between 1.2 million and 1.45 million Albanians to flee Kosovo.

Withdrawal of Yugoslav Forces and Arrival of KFOR

The war ended with the signing of the Kumanovo Agreement on 9 June 1999, whereby Yugoslav and Serbian forces agreed to withdraw from Kosovo. On 12 June, NATO’s Kosovo Force (KFOR) entered the province to restore stability and oversee the return of refugees.
The KLA subsequently disbanded, though some members later joined Albanian militias in the Preševo Valley or took part in the 2001 insurgency in Macedonia. Others integrated into the newly established Kosovo Police.

Human Impact and Aftermath

The conflict resulted in over 13,500 people killed or missing. After the war, around 200,000 Serbs, Romani and other non-Albanian civilians fled Kosovo, citing fear of reprisals, attacks, and lawlessness. Many who remained suffered discrimination or violence. A UN-administered court concluded in 2001 that a systematic campaign of terror had been conducted against Kosovo Albanians but ruled that it did not amount to genocide.
The ICTY later convicted six senior Yugoslav and Serbian officials, and one Albanian commander, for war crimes committed during the conflict.

Wider Historical Context

Serbian–Albanian tensions in Kosovo long predated the 1998–1999 conflict. Episodes of violence, forced migration, and competing nationalist aspirations shaped relations from the late Ottoman period through both world wars and the socialist era. Tito’s post-war federal structure sought to stabilise ethnic relations by acknowledging multiple national identities within Yugoslavia, including autonomous status for Kosovo. However, the system’s fragility and rising nationalism in the 1980s set the stage for renewed conflict.