Air raid sirens sound in Serbia to mark the tenth anniversary of NATO bombings in the country

Serbians are marking the tenth anniversary of the start of the NATO air assault on the capital Belgrade and other major population centers.A decade ago today - NATO launched military strikes on Serbian civilian areas as part of efforts to push the country's forces out of Kosovo - then a Serbian province. NATO said Serb troops had committed atrocities against ethnic Albanians there. Last year, Kosovo unilaterally declared its independence from Belgrade, and relations between the two sides remain tense.