Updated

NATO sent reserve forces to Kosovo on Monday after a week of violence near the border with Serbia left one Kosovo police officer dead and brought peacekeepers under fire.

The additional troops are not permanently beefing up the alliance force in Kosovo, but providing immediate relief for soldiers who have been on duty since the crisis began, NATO spokeswoman Carmen Romero stressed.

The latest violence was sparked by a Kosovo police action to control two disputed border crossings in northern Kosovo, sparking anger among local Serbs who want the former province of Kosovo to remain part of Serbia. After police withdrew, a mob of Serb militants one border post ablaze and fired on NATO peacekeepers sent to restore order.

"This is not an escalation, on the contrary, the situation is calming down," Romero said. "This is a pure tactical decision to relieve our forces and be on the safe side."

Romero declined to discuss the size of the reserve force. But an official who could not to be identified under standing rules said a battalion-sized unit based in Germany had been activated. A battalion usually numbers about 700 troops.

Romero declined to say when the deployment would commence.

The alliance routinely designates specific units in member nations to serve as reserve forces for its active-duty troops.

NATO still has nearly 6,000 troops based in Kosovo, 12 years after the war that ended Serbia's rule there.

NATO has stressed it remains "status neutral" in the dispute between Kosovo's government and the Serb minority.

"NATO is not taking sides," Romero said. The force "will bless any agreement reached by the two sides."