(CNN) -- The United States officially recognized Kosovo -- the Balkan state which split from Serbia on Sunday -- as an independent nation on Monday, Secretary of State Condoleezza Rice said in a written statement.
"We congratulate the people of Kosovo on this historic occasion," Rice said. "President Bush has responded affirmatively to a request from Kosovo to establish diplomatic relations between our two countries."
European Union nations Monday were also starting to recognize Kosovo as the world's newest nation, agencies have reported.
Britain, Germany and France were among EU member states which said they would establish official diplomatic ties with the Balkan state following a meeting of European ministers in Brussels Monday, according to The Associated Press. "We intend to recognize Kosovo," France foreign minister Bernard Kouchner told reporters afterwards.
EU foreign ministers decided that the bloc's 27 member nations should decide individually whether to recognise Kosovo.
They agreed its secession was a one-off under international law, justified by Belgrade's oppression and rejection of a negotiated final status for the region.
But other EU nations including Greece, Spain and Romania have signalled that they would not follow suit amid concerns about the precedent that such a move would set.
Facing severe economic problems and high unemployment, Kosovo is banking on the support of Western powers including the United States and key EU nations to give it immediate backing.
But while independence is broadly favored by the West, U.N. Security Council members Russia and China have expressed outright opposition and "grave concern" over Kosovo's unilateral decision.
Serbia insists it will not respond with violence to Kosovo's sovereignty claim, although it refuses to recognize the move.
In the Serb-dominated northern Kosovo town of Mitrovica, scores of Kosovo Serbs took to the streets waving Serbian flags in a demonstration against independence.
U.S. President George W. Bush said he acknowledged Monday Kosovo's declaration of independence from Serbia, but stopped short of a formal recognition.Watch mixed reaction to independence declaration
"We'll watch and see how the events unfold today," Bush told NBC News from Tanzania. "But the Kosovars are now independent. It's something that I have advocated, along with my government."
Asked earlier Monday whether the United States would officially recognize Kosovo, U.S. Secretary of State Condoleezza Rice said: "Stay tuned."
"We will not recognize Kosovo independence because we do not consider it in line with international law," said Spain's foreign minister, Miguel Angel Moratinos before Monday's meeting. "There is a division within the international community, division in the Security Council and division in the European Union, and we don't know what will be the consequences for the region," he said. Spain has struggled with separatists in its Basque region.
"Our position is that this declaration should be disregarded by the international community," as well as by the head of the U.N. mission in Kosovo, Moscow's U.N. ambassador, Vitaly Churkin said on Sunday.
In Beijing Monday, Chinese Foreign Ministry spokesman Liu Jianchao expressed grave concern over Kosovo's move for independence.
"Kosovo's unilateral act can produce a series of results that will lead to seriously negative influence on peace and stability in the Balkan region ..." Liu said, according to China's Xinhua news agency. He called on Kosovo and Serbia to seek a solution under international law.
Fireworks lit the skies and crowds filled the streets of Kosovo's capital Sunday after the territory's parliament declared independence from Serbia.
"The day has come," Prime Minister Hashim Thaci, a former separatist guerrilla leader, told his parliament. "From this day onwards, Kosovo is proud, independent and free." Watch how U.N. is divided over Kosovo's future
The province has been under U.N. administration and patrolled by NATO troops since a 1999 bombing campaign that halted a Serb-led campaign against Kosovo's ethnic Albanian majority.
Thousands of people swarmed Pristina's streets ahead of Sunday's parliamentary declaration, singing, dancing and holding signs in freezing wind after the vote was announced. But Serbs consider the territory the cradle of their civilization, and protesters clashed with police outside the U.S. Embassy in Belgrade as the declaration was issued.
Serbia said it will not oppose independence with violence, but Prime Minister Vojislav Kostunica said his country will never accept the establishment of a "false country" on its territory.
Russia expressed similar concerns at Sunday's emergency Security Council meeting in New York.
"Our concern is for the safety of Serbs and other minorities in Kosovo," Churkin stated, adding that Russia will "strongly warn against any attempts at repressive measures should Serbs in Kosovo decide not to comply with this unilateral proclamation of independence."
About 100,000 Serbs still live in Kosovo, making up about 5 percent of the population, and Kostunica said Serbs have been killed or lost their land in the eight-plus years the country has been under international rule. But Fatmir Sejdiu, the nascent republic's president, pledged to create a nation "where all citizens of all ethnicities feel appreciated."
"Today is probably a day of trepidation for some of you, but your property and your rights will be respected in the future," he said.
Former Yugoslav President Slobodan Milosevic launched a crackdown against ethnic Albanian insurgents led by Thaci in 1998 and refused to yield to Western pressure to halt the campaign. When NATO responded by launching airstrikes against Serbia and Montenegro, the last remaining Yugoslav republics, Yugoslav troops drove hundreds of thousands of Kosovars out of the region and killed thousands more.
Milosevic died in 2005 while awaiting trial for war crimes before a U.N. tribunal in The Hague.
The United States and leading European nations, including France, Britain and Germany, have supported Kosovo's move toward independence. But Russia, the Serbs' historical ally, has opposed independence, fearing it would incite other separatist movements in its backyard.
But no country supported the Russian call for the U.N. to declare Sunday's declaration "null and void," said Sir John Sawers, the British ambassador to the world body.
Secretary-General Ban Ki-moon urged all parties "to refrain from any actions or statements that could endanger peace, incite violence or jeopardize security in Kosovo and the region."The European Union decided Saturday to launch a mission of about 2,000 police and judicial officers to replace the U.N. mission that has controlled the province since 1999. And U.S. State Department Spokesman Sean McCormack said the United States had "noted" that Kosovo had declared its independence and was reviewing the issue.