BRUSSELS (AP)--The U.S. will not accept any renegotiation of U.N. proposals to grant Kosovo supervised independence, a senior U.S. official said Tuesday, after NATO expressed unanimous support for the plan which Serbia and its Russian backers oppose. 

"We are not going to be open to any fundamental alteration of that plan," said U.S. Undersecretary of State Nicholas Burns. Speaking to reporters after talks at NATO headquarters, he said the plan "should form the basis of the effort that will lead to an independent Kosovo." 

U.N. envoy Martti Ahtisaari's proposal was presented to the U.N. Security Council on Monday together with an introductory report which states that "the only viable option for Kosovo is independence, to be supervised for an initial period by the international community." 

NATO's Secretary General Jaap de Hoop Scheffer said all 27 NATO nations backed the plan at a special meeting of senior officials. 

"The allies have clearly come out in favor of the Ahtisaari proposals," he told a news conference. "There was a clear and strong sense of unity around the table." 

NATO had previously stressed its support for the U.N. process in finding a solution for Kosovo, rather than for the content of the plan itself. That caution reflected concern among European allies such as Spain and Greece over the prospect of Kosovo gaining full independence. 

Serbia, which wants the province to remain within its borders, has called the plan unacceptable and held out hope for more negotiations. Some politicians have called for Ahtisaari to be replaced, an idea rejected by Burns who said the former Finnish president had done a "first-rate" job. 

The final decision on the plan will be taken by the U.S. Security Council, where Russia has implied it could use its veto power if Serbia's interests are not addressed. Western diplomats are concerned that could lead to Kosovo's ethnic Albanian majority declaring unilateral independence, which could spark a regional crisis. 

De Hoop Scheffer warned either side against resorting to violence to solve the problem, insisting that NATO's 16,000 peacekeepers were ready to handle any unrest. 

Kosovo has been administered by the United Nations since 1999, when NATO airstrikes ended a Serbian crackdown on ethnic Albanian separatists. Diplomats at the U.N. say council would likely have its first formal discussion of the report on April 3. De Hoop Scheffer said he hoped it will be able to resolve the question within a a few months. 

"There is no need for a rush to this through the Security Council, but on the other hand there should be no unnecessary delay," he said.
 
March 27, 2007 13:15 ET (17:15 GMT)