Serbia's top leaders immediately rejected Kosovo's "unilateral and illegal" declaration of independence Sunday, but said they would not use force to reclaim the breakaway province.
Reacting to the declaration by the ethnic Albanian-dominated assembly in the breakaway province, President Boris Tadic urged international organizations "to immediately annul this act, which violates the basic principles of international law."
"Serbia will ... do everything in its power to revoke the unilateral and illegal declaration of independence," Tadic said in a statement.
He urged Serbia's political parties and the 130,000 Serbs living in the province "to remain calm," but stressed that Serbia would "not resort to violence" to achieve its goal of reuniting Kosovo.
Serbian officials have prepared a secret "action plan" they said would not include military action, and warned that Serbia would downgrade relations with any foreign government that recognizes Kosovo's independence.
Belgrade has said it would retain control over areas inhabited by the 130,000-strong Serb minority in Kosovo and that its laws would continue to apply there.
Meanwhile, the country's prime minister, Vojislav Kostunica, lashed out at U.S. President George W. Bush over his support for Kosovo's independence, saying his name would go down in "black letters" in Serbian history.
Top Bush administration officials in the past have vigorously backed Kosovo's independence. The United States also led the 1999 NATO bombing campaign that ended Serbia's rule over the province of 2 million people, 90 percent of them ethnic Albanians.
"America places the policy of force above the U.N. Charter, it is violating international legal norms in order to further its own military interests," Kostunica said in a televised address to the nation.
"This unprecedented case of lawlessness was brought about by the destructive, brutal and immoral policies of force imposed by the United States," he said.
Kostunica said the government will organize a series of peaceful protests against the declaration.
About 150 ultra-nationalists rallied Sunday in front of the U.S. Embassy in Belgrade, chanting slogans against the United States and NATO.