The United States expressed deep disappointment Monday over the boycott by most Serb voters of weekend parliamentary elections in Kosovo. The State Department said U.S. officials will continue to work for a multi-ethnic political future for the United Nations-run Serbian province.

The fact that most of Kosovo's ethnic-Serb minority stayed away from the polls in Saturday's voting is seen as a setback for international efforts to resolve Kosovo's political future.

But the State Department, while expressing disappointment over the development, said the United States remains committed to achieving a stable, secure and multi-ethnic Kosovo.

The United Nations has administered the majority ethnic-Albanian region since 1999, when NATO waged a bombing campaign to end persecution of Albanians by Serb and Yugoslav forces.

The new government to be formed on the basis of Saturday's elections is expected to assume more authority as the U.N. reduces its presence. But news reports say the Serb boycott, which was almost totally effective, has complicated those plans and could delay a political settlement for self-government.

Serb political leaders had called for the boycott, saying that taking part in the election would bolster Albanian moves toward independence.

At a news briefing, State Department Deputy spokesman Adam Ereli congratulated Kosovo authorities for organizing what was generally seen as having been a free and fair election, while lamenting the stand taken by Serb leadership. "We do regret that some politicians discouraged people from voting. We are deeply disappointed that many Kosovo Serbs chose not to vote. It is our view that that decision is self-defeating. Taking part in Kosovo's institutions is the best way for all communities in Kosovo to advance their legitimate interests," he said.

Mr. Ereli said the United States will continue to work with Kosovo's leaders on key issues including progress on building a multi-ethnic future for the area. He said with the election having taken place, the important thing now is to maintain momentum on key issues including political de-centralization.

The pro-independence party of Kosovo President Ibrahim Rugova held a clear lead in early election returns.

Negotiations on Kosovo's political future are expected to begin next year with the main issue being whether Kosovo remains part of Serbia or becomes independent, as favored by most ethnic-Albanians.