Kosovo police say they have increased security in the town of Mitrovica after five hooded assailants crossed from the ethnic Albanian southern part of town into the Serb northern part to a stab a Serb teenager. It was the first serious ethnically motivated incident in years.

Deputy regional commander Besim Hoti said Friday that police are studying surveillance camera video to identify the attackers. He said three policemen have been suspended for failing to stop the teenagers, whose violent intent was clear in the video evidence. The surveillance video was not made public.

The victim is recovering from chest wounds. Hoti said two ethnic Albanians and Kosovo Bosniaks were beaten by Serbs in apparent retaliation following Thursday's stabbing.

Serbia rejects Kosovo's 2008 declaration of independence.