Kyrgyzstan's parliament voted Thursday to close a key U.S. air base in the country — a move that could hamper President Barack Obama's efforts to increase the number of U.S. forces in Afghanistan.

Deputies voted 78-1 with two abstentions for the government-backed bill to cancel the lease agreement on the Manas air base, a transit point for 15,000 troops and 500 tons of cargo each month to and from Afghanistan. The move follows Russia's offer of $2.15 billion in aid and loans to the impoverished Central Asian country.

U.S. Defense Secretary Robert Gates, in Poland for NATO talks, said the United States would consider paying more rent to continue using the strategic base. Speaking after the parliament vote in Kyrgyzstan, Gates said he considers talks still open over the future of the base.

Russia has denied pushing Kyrgyzstan to shut the base, but U.S. officials were skeptical.

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"I think that the Russians are trying to have it both ways with respect to Afghanistan in terms of Manas," Gates said. "On one hand you're making positive noises about working with us in Afghanistan and on the other hand you're working against us in terms of that airfield which is clearly important to us."

Kyrgyz President Kurmanbek Bakiyev — who announced the planned eviction and whose government introduced the legislation — is expected to sign the bill in the coming weeks. Once Kyrgyz authorities issue an eviction notice, the United States will have 180 days to leave the base.

Pentagon spokesman Geoff Morrell said the U.S. has "yet to receive any formal notification of a change in status of Manas so our operations there continue as normal."

"A stable, peaceful Afghanistan is in everyone's interest, including the Kyrgyz people, and Manas is instrumental to our efforts to make that a reality," he said. "However, the base is not irreplaceable and we have alternatives should they be needed."

Widespread public discontent in Kyrgyzstan over the U.S. military presence has been sharpened in recent years by a number of high-profile incidents surrounding the base.

In late 2006, a U.S. serviceman fatally shot truck driver Alexander Ivanov during a routine security check. U.S. officials said Ivanov threatened the serviceman with a knife. On a recent visit to Kyrgyzstan, U.S. Gen. David Petraeus said an investigation into the killing had been reopened.

"So far, no American soldier appeared in court," Kyrgyz foreign minister Kadyrbek Sarbayev told deputies Thursday.

Sarbayev also complained the United States has failed to adequately compensate Kyrgyzstan for $650,000 worth of damage caused to a civilian Tu-154 plane when it collided with a U.S. KC-135 tanker aircraft.

The only opposition to the Kyrgyz bill came from the Social Democrat party, which argued the shuttering of Manas could undermine national security.

The United States is trying to finalize details of an alternative overland supply route to Afghanistan amid concerns over worsening security in Pakistan. Some 75 percent of U.S. supplies currently travel through Pakistan, where militants have stepped up attacks on truck convoys destined for U.S. bases.

Washington has already received permission from Russia and Kazakhstan to transport non-lethal supplies for Afghanistan by rail. It hopes to secure similar guarantees from Uzbekistan, which has a border and transportation links with Afghanistan.

NATO spokesman James Appathurai said the Kyrgyz vote was "an inconvenience and a decision to regret, but we can certainly absorb it."

"There is plenty of flexibility in the logistical supply chain for NATO," he added. "There are alternatives; they will be used."

Around 100 containers of non-lethal supplies bound for Afghanistan left by train Wednesday from Latvia for Russia, U.S. diplomats said.

Also Thursday, a delegation of U.S. military transportation officials arrived in another former Soviet state in the region, Tajikistan, which shares an 810-mile border with Afghanistan.

The officials will study Tajikistan's transportation infrastructure and evaluate the potential for shipping nonmilitary cargo through the country to Afghanistan, the Tajik Foreign Ministry said.