In the spring of 1999, NATO began the first combat operations since its formation in 1949 by conducting an air campaign against Serbian militias and Federal Republic of Yugoslavia (FRY) troops in Kosovo in order to try and stop the ethnic cleansing of Muslims and Albanians there. After weeks of fruitless bombing in uncontested air space, the Milosevic regime refused to come to the negotiating table, and even accelerated their program of ethnic cleansing.
Despite being another historical example of air power failing to win a war by itself, NATO doubled down on failure and expanded their air campaign to include targets inside Serbia and Montenegro. On 7 May 1999, while attacking infrastructure targets in Belgrade, NATO accidently bombed the Chinese Embassy, killing three Chinese diplomatic workers, wounding 30 more, and created a massive international incident. In June, only the threat of NATO land power brought the Slobodan Milosevic and the FRY govt to the negotiating table after his Russian backers offered no counter. In June, the UN authorized peacekeepers to the region, to include Russian and NATO troops, to stop the ethnic cleansing and allow the return of refugees.