BELGRADE, Serbia - Thousands of angry Serbs were converging on Belgrade Thursday to attend a rally to protest Kosovo's declaration of independence, raising fears that the gathering could trigger street violence.

Schools were closed and the state railway company made free trains available to bring protesters to the rally. Local media reports on Thursday morning said crowds of thousands were already making their way to the capital for the afternoon rally.

Organizers say the "Kosovo is Ours'' event will demonstrate Serbia's commitment to holding on to the province of 2 million people.

The demonstrators are scheduled to rally in front of Serbia's parliament and then march to the Saint Sava Orthodox temple for an evening service.

More than a dozen nations have recognized Kosovo's declaration of independence, which was made on Sunday. They include the United States, Britain, France and Germany.

But the move has been rejected by Serbia's nationalist government along with the ethnic Serbians who populate northern Kosovo. Russia, China and numerous other nations have also condemned the move, saying it sets a precedent that separatist groups around the world will seek to emulate.

There are fears that Thursday's rally could spark renewed rioting by ultra-nationalists who attacked the U.S. Embassy, McDonald's restaurants and other Western interests in the capital earlier this week.

They also attacked the offices of the pro-Western Liberal Democratic Party in several towns.

"We are convinced that the state organs are behind these attacks,'' the party said in an open letter to the government published Thursday in the media.

Critics say attacks could be a prelude to the silencing of the opposition and pro-Western politicians in the Balkan republic, reminiscent of the era when the country was run by Slobodan Milosevic.

His regime also organized giant rallies by bussing in supporters and schoolchildren to demonstrate public support for the wars Serbia waged in Croatia, Bosnia and Kosovo.

The U.S. Embassy warned American citizens to stay away from the rally, saying the event may turn "confrontational and possibly escalate into violence.''

"Businesses and organizations with U.S. affiliations may serve as focal points for these demonstrations,'' a statement said.

Germany's defense minister was visiting Kosovo Thursday, a day after the German Cabinet approved that country's recognition of Kosovo as an independent country.

Franz Josef Jung praised NATO's role in securing Kosovo's tense north after the declaration. Ethnic Serbs living in northern Kosovo have attacked and torched border outposts. There have also been protests there in recent days, and several empty UN vehicles have been destroyed in explosions. No one has been injured.

The defense minister pledged German support in providing troops for the 16,000-strong NATO peacekeeping force and assisting Kosovo's local security forces.