(Adds British, U.S. and Russian envoys, Kosovo prime minister; paragraphs 7-13, 17-20)

By Louis Charbonneau

UNITED NATIONS, April 21 (Reuters) - Serbia's president said on Monday that Serbs in the new state of Kosovo should participate in local Serbian elections next month, but Britain and the United States said this would be unwise and illegal.

Serbia, which says it will never recognize Kosovo's Feb. 17 declaration of independence from Belgrade, will hold local and parliamentary elections on May 11.

The United Nations, which has administered Kosovo since 1999, says the participation of Kosovo Serbs in Serbia's local elections would violate U.N. rules and would not be valid.

But in the written text of remarks prepared for delivery at a Security Council briefing on Kosovo, Serbian President Boris Tadic said it was vital for Kosovo Serbs to be able to vote in the local elections. The population of Kosovo's north is predominantly Serbian.

"We believe it is important that everywhere in Kosovo, where (Serb) citizens recognize the Republic of Serbia as their state, they choose in a democratic way their own municipal, as well as parliamentary, representatives," Tadic said.

The U.N. mission in Kosovo (UNMIK) has indicated it did not object to Kosovo Serbs voting in the parliamentary election as they have done before, but Kosovo's ethnic Albanian leaders say local polls were a threat to the sovereignty of the new state.

Officially, UNMIK remains in control of Kosovo.

British Ambassador to the United Nations, John Sawers, told reporters the U.N. administrator of Kosovo, Joachim Ruecker of Germany, reported to the council that he opposed the holding of Serbian local elections in Kosovo.

"His judgment is that elections now, especially elections on an ethnic basis, would be divisive and unhelpful," Sawers said. "We look to Serbia to reverse its decision to try to hold these ethnically based elections inside Kosovo."

'PROVOCATION'

U.S. Ambassador Zalmay Khalilzad told reporters the local elections would be "unhelpful" and "illegal."

"This is unacceptable," he told the council. "President Tadic -- efforts to conduct these municipal elections are a provocation, and I call on you not to proceed with them."

Russian Ambassador Vitaly Churkin sided with the Serbs, saying Serbian local elections should go ahead in Kosovo.

"We believe that the Serbs have every right to conduct their parliamentary and municipal elections when they see fit," he told reporters after the council meeting.

Russia has used its ability to veto U.N. Security Council action to prevent any resolution legitimizing Kosovo's independence or the EU role in the breakaway Serbian province.

Tadic said Kosovo Serbs did not trust authorities in Pristina, nor would they cooperate with a mission of European Union police and justice officials (EULEX) that plans to formally take over from the United Nations in June.

The European Union decided in February to deploy a 2,200-strong mission to help build Kosovo's institutions, intended to replace UNMIK, even though some EU member states -- similar to Serbia and Russia -- have not recognized Kosovo.

Khalilzad sharply criticized Tadic for urging Kosovo Serbs not to cooperate with the authorities in Pristina.

"We are also concerned by Belgrade's actions to pressure Kosovo Serbs from cooperating with authorities in Pristina or from interacting with their Albanian neighbors," he said. "Belgrade's position runs contrary to the principle of multi-ethnicity that the U.N. has sought to foster in Kosovo."

Kosovo's prime minister, Hashim Thaci, who fought in the 1998-1999 guerrilla war against Serbia, also addressed the closed-door session of the council.

Afterwards Thaci told reporters that holding local Serbian elections in Kosovo would be "illegitimate" and vowed to ensure that Kosovo's government would include Serbs and Albanians.

AlertNet news is provided by