Troops of the North Atlantic Treaty Organization (NATO) and European police have increased patrols in and around Kosovo's volatile northern town of Mitrovica, after at least six people were injured in clashes between Serbs and ethnic Albanians late Friday. Police officials say explosions also destroyed cars and properties.

A tense calm returned to Kosovo's second largest and most ethnically divided town of Mitrovica, where since late Friday about half a dozen people, including fire fighters, were wounded in clashes between Serbs and ethnic Albanians.

There were violent protests followed by two huge explosions that rocked Mitrovica, destroying cars and damaging properties. Police and fire fighters rushed to the scene as the first blast destroyed at least seven cars near a bar in the town's Serb district. Security officials said Serbs then set two Albanian shops alight.

But as a fire brigade arrived to put out these blazes, a second explosive device apparently detonated, hampering efforts to secure the area.

Troops of the Western military alliance NATO and European Union police stepped up their presence around Mitrovica, and armoured vehicles were seen patrolling the streets.

The latest clashes came after a Serb teenager was reportedly hurt by two knife-wielding Albanians on Tuesday, who were later detained. That incident prompted hundreds of Serbs to burn down several Albanian shops and to damage cars with Kosovo license plates.

Observers say the latest violence also reflects deep rooted divisions between the Serb minority of 120,000 people, and the two-million strong ethnic Albanian community of Kosovo.

Serbs are angry that Kosovo's government declared the territory independent from neighboring Serbia, last year. Kosovo's secession in February occurred nearly a decade after NATO bombings ended a Serbian military crackdown on independence seeking ethnic Albanians.

Friday's fighting underscored Western concern that Mitrovica will become once again a major flashpoint of ethnic fighting, and attacks against Western peacekeepers. The town was already the scene of deadly clashes in March between Serbs and international forces.