WASHINGTON — The implications of American and European recognition of an independent Kosovo are coming into focus, with the burning of America’s embassy in Serbia foreshadowing potential clashes over the borders of Kosovo itself.

Yesterday, as the American Embassy in Belgrade burned, the Associated Press reported that vigilantes set afire a U.N. vehicle in the Serb minority province of Mitrovica on the border between Kosovo and Serbia. Meanwhile, a United Nations-run court building in the province came under attack again from protesters throwing rocks, in what could be an effort from the Serb minority to impose a de facto secession from the newly independent Albanian majority country.

The man who served as the U.N. regional administrator for Mitrovica and northern Kosovo in 2000, a retired American major general, William Nash, yesterday said he feared that violence loomed for the new country.

“There have been attacks at the borders, an expression of great distaste. They have reacted to that,” General Nash, who is retired from active duty, said. “The potential for further violence is there. My great fear is that an act of provocation will be met by an act of retaliation that in turn escalates to something that gets out of hand.” The general went on to say he thinks the international force will likely have to increase around-the-clock patrols to prevent further clashes.

The vice president of peace and stability operations for the U.S. Institute of Peace, Daniel Serwer, yesterday said he anticipated a move from Serbia to try to create at least a de facto partition in Kosovo for the Serb minority in the Mitrovica area. “The Serb position on Kosovo is that we have a right to the land and we don’t care about the people,” Mr. Serwer, who served as President Clinton’s special envoy to the Bosnian Federation during the Bosnian war, said. “What there is a potential for, is Serbia seizing the north and trying to precipitate an Albanian effort to seize part of Macedonia. I don’t see the Albanians falling for that, though.”

In Belgrade, the capital of Serbia, a crowd estimated at more than 100,000 took to the streets to protest recognition of what was seen by Serbs as the secession of a province of their own country. In 1998 Slobodan Milosevic sent his army to Kosovo and began rounding up Albanian Kosovars from their homes in an act that prompted NATO and America to begin a bombing campaign of Belgrade that ultimately forced the Serbian dictator to stand down.

The protesters burned the outer perimeter of the American Embassy, where a man was found by firefighters burned to death. The embassy later confirmed that all embassy staff were accounted for. Also vandalized were a McDonald’s restaurant and a store selling Nike sneakers, according to wire reports.

The street protests are a bitter irony for Mr. Clinton’s foreign policy team especially, considering that the last time protests of that size were seen in Belgrade was in 2000, when Prime Minister Kostunica led marches on the parliament that ultimately forced Milosevic to give up power.

In 2000, Mr. Kostunica was praised as a liberal visionary in Washington. Today he is leading crowds of Serbs in Belgrade insisting that Kosovo remain part of Serbia.

Speaking to supporters in Belgrade this week, the prime minister said, “America forced Europe to follow it in unprecedented violence demonstrated against Serbia. Europe has bent its head today and that is why it will be responsible for far-reaching consequences that this violence will have on the European and world order. This act has above all humiliated the E.U., not Serbia. Serbia rejected to be humiliated, respecting firmly the law and rejecting to obey force.”

Mr. Serwer yesterday compared Mr. Kostunica to the anti-American Venezuelan strong man Hugo Chavez. “Look, they have done nothing to prepare their people for this. They have been beating the war drums, not just the last week, but especially the last week,” he said. “Some of the things Kostunica has said about President Bush and America are worthy of Hugo Chavez.”

The spokesman for the State Department, Sean McCormack, expressed similar concerns about statements from high Serb officials. “You don’t want to create an atmosphere where people think it’s okay to express political unhappiness to vent political emotions in a violent way,” he said, stopping sort of linking statements from Serb leaders directly to the demonstrations against the embassy. “That is unacceptable. It’s completely unacceptable and there’s no political justification for the kinds of acts that we saw today in attacking our embassy.”

At the United Nations, America succeeded in winning a U.N. Security Council resolution condemning and expressing outrage at the violence against the embassies of America, Bosnia, Canada, Croatia, Germany, and Turkey. At the insistence of Russia, a traditional ally of the Serbs, the resolution also asserted that Serb authorities were doing all they could to restore order.