Kosovo has accused Serbia of abducting two Kosovar Albanian police officers patrolling their joint border.
Belgrade said the two men, armed with guns and automatic rifles, were detained on Serbian-controlled territory in the region of Merdare.
But Kosovo's Interior Minister Bajram Rexhepi said the two officers had been "kidnapped" within Kosovo-controlled territory.
Majority-Albanian Kosovo declared independence from Serbia in 2008, but Belgrade does not recognize the secession.
After signs of progress in relations this year, tensions have again been rising over Serbia's intention to hold local elections in some Serb-populated areas of Kosovo in May.
Based on reporting by Reuters, AP, and AFP