About 250 German peacekeepers have arrived in Kosovo, the first of NATO's 700-strong quick reaction force being sent there ahead of next month's election in neighboring Serbia.

Sporadic violence between minority ethnic Albanians and majority Serbs has occurred in northern Kosovo since the end of war in Kosovo in 1999. That's because Serbs reject Kosovo's claim of independence and want the territory to be part of Serbia.

Serbia plans on May 6 to have voters choose mayors for local authorities, and Kosovo has vowed to stop those elections, saying they would undermine its 2008 claim of statehood.

A NATO spokesman, Maj. Marc Stummler, said Wednesday rising tensions have prompted the alliance to bolster its 6,000-strong Kosovo mission. He says the reinforcements are made up of 550 German soldiers and 150 Austrian troops.