MITROVICA, Kosovo — Thousands of Serbs rallied yesterday in this tense, divided town and vowed never to let go of a region that they, like ethnic Albanians, consider their homeland.

For all the rhetoric unleashed as world powers slowly started recognizing an independent nation called Kososov, it seemed unlikely that large-scale violence would erupt.

More than 16,000 NATO troops patrol Kosovo, and Prime Minister Kostunica of Serbia, speaking in the Serbian capital of Belgrade, issued a statement yesterday calling on Serbs to restrain themselves.

Protesters here burned a picture of an American flag and charged an icicled bridge that leads to the Albanian section of town, but they stopped short of crossing it.

Instead, they chanted angry slogans, pumping their fists in the air and waving red-white-and-blue Serbian flags, and they sang traditional folk songs.

“You can’t just take part of someone’s state,” said Sasa Cirkovic, 18, a Serb student. “A state cannot be created inside another state.”

Just across the bridge, the picture was very different. Red Albanian flags emblazoned with a black eagle fluttered from shops, homes and mosques, and relatively calm residents soaked up what they considered to be a new, if not quite tangible, freedom.

“The thing is, the Serbs have to accept the reality, and reality has changed,” said Mehmat Haxhani, 50, a boxing coach and elementary school teacher. “We are another country now.”

U.N. officials who have administered Kosovo for almost a decade regard Mitrovica as a potential flashpoint. NATO troops and U.N. police were patrolling the town and deployed at the bridge.

Straddling the Ibar River, Mitrovica in many ways symbolizes the difficulties that lie ahead following Sunday’s declaration of independence by the ethnic Albanian government of Kosovo. On the northern side of the river, abutting Serbia, live Serbs, enraged, sad and humiliated; to the south are confident, ethnic Albanians feeling newly empowered. There is mistrust all around and deep uncertainty over the future. The plight of the roughly 100,000 Serbs who still live in Kosovo (a larger number was forced to flee) remains a major sticking point. Kosovo’s officials, under international pressure, are promising to protect Serbs and other minorities.

Hard-line Serb leaders in Mitrovica are saying they would secede from any breakaway Kosovo, in a sense creating a partition within a partition.

“Serbia must decide whether it is willing to use its army to defend Kosovo,” Marko Jaksic, a Kosovo Serb leader, told the rally in Mitrovica. “All military force must be used to protect our brothers!” “Kosovo is Serbian!” the crowd chanted.

Signs read: “Russia, help!”

There were men in business suits, women in full-length fur coats, parents carting their children and scores of youths.

“I remain here and will stay here,” said a Serbian woman who would give only her first name, Ana, 52. “Kosovo will never be independent. We will reply to their violence with violence. Why should we be afraid?”

There have been scattered incidents of rock-throwing and vandalism, and a hand grenade thrown at a U.N. building in Kosovo early Monday torched a U.N. vehicle. Police fought back hundreds of Bosnian Serb students attempting to march on American diplomatic offices in the Bosnian Serb town of Banja Luka.

As feared, Kosovo’s independence is inspiring some Bosnian Serbs to demand their liberation from the multi-ethnic state of Bosnia.

Belgrade turned nasty Sunday night, hours after Kosovo’s declaration, with attacks on Western embassies by rampaging gangs. But yesterday, peaceful demonstrations were held in the Serbian capital and other parts of Serbia. Thousands of people crowded into Belgrade’s Orthodox cathedral for a special prayer service for Kosovo Serbs.