WASHINGTON - The Obama administration scrambled Wednesday to come up with an alternative to a crucial United States air base in Central Asia, used to supply the growing military operation in Afghanistan, after the president of Kyrgyzstan ordered the American base in his country closed.
Defense and State Department officials said they had concluded that Russia had pressed Kyrgyzstan, a former Soviet republic, to expel the Americans. Russia has promised not to impede the American-led fight against the Taliban in Afghanistan, but has also sought to push United States forces out of bases it began leasing in Central Asia in the wake of the Sept. 11, 2001, terrorist attacks.
The Kyrgyz Parliament planned to vote next week on a measure that would close the base at Manas, a major air hub for troops and cargo. Loss of the base would present a significant problem for the Obama administration as it deploys as many as 30,000 additional troops to Afghanistan over the next two years. Taliban attacks have made another prime supply route to Afghanistan - an overland pass through Pakistan - highly unreliable.
A senior State Department official said that negotiations with Kyrgyzstan over the base had been halted and that the alternatives under consideration included bases in Europe and the Persian Gulf, as well as a possible expansion of existing bases in Afghanistan.
The United States has leased the Central Asian base since after the 2001 invasion of Afghanistan, but American officials said they believed that Russia was using an offer of more than $2 billion in loans and grants to Kyrgyzstan to force the United States out of the region, colloquially referred to as "the Stans."
"The motivation is to have a strong bilateral relationship with the Stans that prevents the Stans from hosting U.S. or NATO facilities on their soils," a Defense Department official said.
About 15,000 personnel and 500 tons of cargo pass through Manas each month. The base is also the home of large tanker aircraft that are used for in-air refueling of fighter planes on combat missions over Afghanistan.
The American officials, who insisted on anonymity because of the delicacy of the negotiations, said that it was possible that the United States would resume talks with Kyrgyzstan but that for the next weeks the United States would be investigating whether some of the functions of the base could be relocated, perhaps to more than one place.
The State Department official said it was still possible that the United States might offer Kyrgyzstan more compensation for the base after the other alternatives and their costs had been explored. "Once we evaluate what this is really worth to us, we'll talk to them about money," he said. The United States calculates that it pays Kyrgyzstan more than $150 million in assistance and compensation each year. But the State Department official said that only a portion of that money went directly to the Kyrgyz government. "Frankly, we haven't been excessively generous," the official said.
The State Department official said that "fundamentally it comes to money, and the Russians are trying to buy us out."
A statement by the Kyrgyz government on Wednesday argued that the American mission in Afghanistan had outlasted its original goals, the terrorist threat there had "been removed," and that NATO airstrikes in Afghanistan had caused unacceptable civilian casualties.
The Kyrgyz president, Kurmanbek Bakiyev, announced the decision on Tuesday in Moscow, where his impoverished country won $150 million in aid and the forgiveness of $180 million in debt in addition to the $2 billion in loans. Russian officials claimed that the announcement of the base closure was purely coincidental, but Russia has long resented the United States presence in Central Asia.
If the measure passes the Kyrgyz Parliament, as expected, Washington would have 180 days to close the base. The senior Defense official said the closure "has all the earmarks of being a done deal."
Russian officials took pains on Wednesday to reassure President Obama that they hoped to cooperate with him in Afghanistan and elsewhere. But the conciliatory words sounded peculiar beside the blunt fact of the base closure, which seemed to communicate that American plans in the region should be coordinated with Moscow.
"The calculation behind the Russian move is that the Americans have not so many alternatives," said Fyodor A. Lukyanov, the editor of Russia in Global Politics. "If you need something there, you should go not to Bishkek but to Moscow."
Russian leaders also hope to secure concessions from Mr. Obama on a variety of issues, among them planned missile defense facilities in the Czech Republic and Poland, revamped security structures in Europe, and a renegotiation of the Start I arms treaty.
President Dmitri A. Medvedev said Wednesday that Russia and its allies were ready for full-fledged, comprehensive cooperation with the United States and other coalition members in fighting terrorism in the region. But he also laid out his own view of the best approach in Afghanistan, with veiled criticism of the United States.
"Democracy cannot be forced - it must grow from within," he said. "It's not the number of bases that matters. It would be good if that would reduce the number of terrorists, but the fight against terrorism is not limited to building up military forces."
But by stressing that they are ready to search for alternatives in Europe, the Persian Gulf and Afghanistan itself, the Americans also appeared eager to signal that they would not allow Russia to dictate the terms of its engagement in Afghanistan or the region.
This is not the first time that United States officials have tangled with Kyrgyzstan over the base at Manas. During negotiations this summer, the State Department spokesman Sean McCormack said the United States would pay more than $150 million in assistance and compensation for the base this year. At the time, a government statement said the United States had contributed more than $850 million to support democracy, economic development, aid projects and security in the Kyrgyz Republic since its independence from the Soviet Union.
At a news conference in Moscow on Tuesday, Mr. Bakiyev complained about a 2006 incident in which a United States serviceman had shot a Kyrgyz truck driver on the base, and said Washington had also ignored his requests for more money.
"Eight years have passed," he said. "We have repeatedly raised with the United States the matter of economic compensation for the existence of the base in Kyrgyzstan, but we have not been understood."
Kyrgyzstan's close relations with the United States have long unsettled Russia and China, which both have military interests in the region.
In 2005, the country appeared to move further into Washington's orbit after a popular uprising, supported in part by the United States, toppled the corrupt and increasingly authoritarian government of Askar A. Akayev, sending the president fleeing across the border. The bloodless coup was part of a wave of popular revolts, known as color revolutions, that remain a source of anger and suspicion among Russian officials, who consider them Washington-hatched schemes meant to undermine Russia's influence in the region.
Elisabeth Bumiller reported from Washington, and Ellen Barry from Moscow. Alan Cowell contributed reporting from London.