The State Department's top European affairs expert says the relative quiet and political success of Kosovo since February has silenced critics who forecast dire scenarios for the region, including ethnic violence and refugee flows.

But Assistant Secretary Fried acknowledges continued challenges for the fledgling state, including a still-lagging economy, a restive Serb minority in the north, and political thuggery he says may be inspired by some officials in Belgrade.

The majority-ethnic Albanian former Serb province, which had been administered by the United Nations since 1999, declared its independence in February over the strong objections of Serbia and its main diplomatic ally Russia.

In a talk with reporters, Fried said an independent Kosovo has now been recognized by 43 countries including along with the United States most of Europe and a majority of U.N. Security Council members.

Under questioning he rejected the notion that Russia's refusal to recognize Kosovo, and by extension its refusal to allow recognition by the Security Council, dooms Kosovo to semi-statehood.

"It is a completely-independent country, whether or not there is a U.N. resolution that says so. It is independent," Fried said. "It's been recognized as independent by two-thirds, of Europe, Japan, Australia. It is an independent country. I regret very much that Russia chose to make this harder rather than easier, and thereby making it harder risks stability, and making it harder put as risk Serbia's European future. It was not helpful."

Fried said he hopes that with time, Moscow will become less strident and obstructionist over Kosovo and will not try to prevent the new moderate government in Belgrade from pursuing what he called a European future.

He dismissed, as having no legal status, the separate parliament declared by ethnic-Serbs in northern Kosovo late last month. He said many Kosovar Serbs are prepared to accept the new political reality but are afraid to say so - intimidated by what he said is rampant thuggery by Serb extremists, some of whom cross into Kosovo from Serbia.

"You have Serbs coming over, and it is sometimes hard to tell whether they're sort of private nationalists, semi-connected with the government, or official," Fried said. "There seem to be some of all of them, and the Serbs should not be sending over, or supporting thuggery. That's not responsible. And we hope the new government will act in a responsible way."

Fried said the United States will commit $400 million in aid over the next four years at a donors' conference for Kosovo being convened by the European Union late next week.

He said he expects the conference to raise more than one billion dollars overall to help boost the economy of the new state, which is one of the poorest parts of Europe with an unemployment rate about 40 percent.