MOSCOW (Reuters) - Russian-backed coup or not, the uprising in Kyrgyzstan means the United States may have to bargain hard to keep its last military base in Central Asia.

Turmoil in Kyrgyzstan has thrust the fate of the Manas air base -- which is crucial for fighting the Afghan war -- to the forefront of rivalry between the United States and Russia.

Russia has long dreamed of evicting the United States from Central Asia and a Russian official said on Thursday that Moscow would urge the interim Kyrgyz government to shut the U.S. base.

Suspicions of the Kremlin’s hand in the unrest were raised when Russian Prime Minister Vladimir Putin became the first world leader to recognize the authority of the self-proclaimed government, just hours after it took power.

Washington has been more guarded, refusing to endorse either President Kurmanbek Bakiyev or the self-proclaimed government leaders, some of whom have already raised the specter of shutting the base.

China, which shares a land border with Kyrgyzstan, has been largely silent.

“Russia was very quick to act. Both China and the U.S., by comparison, were caught on the hop,” said Nick Day, chief executive of business intelligence firm Diligence LLC.

“Russia is going to dominate Kyrgyzstan and that means problems for the U.S,” he said. “Russia will use this as a lever in negotiations with America.”

Putin, who is considered by most Russians to be the country’s paramount leader, has denied involvement.

“Neither Russia, nor your humble servant, nor Russian officials have any links whatsoever to these events,” he said.

But countering the dominance of the United States is one of Putin’s guiding principles in world affairs and the Manas base would be a strong card to play in negotiations with Washington on a host of issues ranging from missile defense to WTO entry.

The base is crucial for President Barack Obama’s plans to send more U.S. soldiers into Afghanistan and last month about 50,000 troops passed through the base.

Russia also has a military base in the country and had tried to get a second under Bakiyev.

BROKEN PROMISES?

Russia’s leaders were infuriated by what they viewed as a Bakiyev’s betrayal over a pledge made while on a visit to Russia in 2008 to shut the base.

Bakiyev secured at least $2 billion in aid and loans from Russia before making the pledge, but later agreed to let the United States keep leasing the base, albeit at a higher price.

“In Kyrgyzstan there should be only one base -- Russian,” a senior Russian official told reporters in Prague after Obama and Dmitry Medvedev signed a landmark treaty to reduce vast Cold War arsenals of nuclear weapons.

“Bakiyev did not fulfill his promise about the withdrawal of the American base,” the Russian official said.

“That shows the Russian attitude better than anything else,” said Paul Quinn-Judge, Central Asia director for the International Crisis Group.

“The lease on the base is up for renewal and, looking at the comments, I would say the Russians are already pushing,” said Quinn-Judge, who is based in Bishkek. “How far the Russians are going to push, on that I have no idea.”

The leader of the Kyrgyz provisional government, Roza Otunbayeva, said the base deal with the United States would be preserved but cautioned there were “still some questions on it.”

Allies of Otunbayeva have been more hawkish, warning that the lease on the base could be shortened. The new government is seeking financial and humanitarian aid from Moscow.

“Russia played its role in ousting Bakiyev,” Omurbek Tekebayev, a former opposition leader who is now in charge of constitutional matters, told Reuters.

“There is a high probability that the duration of the U.S. air base’s presence in Kyrgyzstan will be shortened,” he said.

Some of Kyrygzstan’s new leaders say Washington closed its eyes to rights abuses under Bakiyev because of the base, though many members of the interim government have sympathy with the West.

Still, analysts said Kyrgyzstan’s leaders understand the U.S. base is the impoverished country’s only major card to play on the world stage. To give it to Russia would mean complete dominance by Moscow.

“Any future Kyrgyz government will need the money and shoulder the political flak,” said James Nixey, analyst at London-based think tank Chatham House.

“But the situation is inherently worrying in a region that has taken on a new importance since 9/11 and the ‘Global War on Terror’.”