BELGRADE, Serbia (AP) — Serbia is warning Kosovo it will defend "every inch of its territory," including its former province where Serbs allegedly are under threat from Kosovo Albanians.

Serbian President Tomislav Nikolic issued the warning Sunday after a Serbian train, with signs "Kosovo is Serbian," was halted Saturday before it entered Kosovo due to reports of a planned attack by ethnic Albanians.

Nikolic says: "Yesterday, we were on the verge of clashes." Escalating the tensions, he accused Kosovo's Albanians of provoking "war."

Kosovo declared independence from Serbia in 2008, but Serbia does not recognize the split and has sought to maintain influence in Kosovo's north, where most of the country's Serb minority is located.

NATO-led troops are controlling Kosovo's borders following an intervention in 1999 to stop a bloody Serbian crackdown against ethnic Albanian separatists.