Bishkek, Kyrgyzstan ? Kyrgyzstan’s president signed a bill today to close a key U.S. air base used as a staging post for military operations in Afghanistan, a step that could impede American plans to send more troops to the Afghan war.

President Kurmanbek Bakiyev’s signing of the law was the final step before Kyrgyz authorities issue an eviction notice, which will give the United States 180 days to vacate the base.

U.S. officials have said they consider talks on the future of the base still open, indicating there could be negotiations about the amount to be paid for maintaining the base.

“We are prepared to look at the fees and see if there is justification for a somewhat larger payment,” U.S. Defense Secretary Robert Gates said Thursday. “But we’re not going to be ridiculous about it.”

Kyrgyz lawmakers voted overwhelmingly Thursday in favor of the government-backed bill to cancel the lease on the Manas air base, a transit point for 15,000 troops and 500 tons of cargo each month to and from Afghanistan.

Bakiyev announced the closure of Manas earlier this month, complaining the United States was not paying enough rent for the base. His announcement came shortly after he secured $2.15 billion in aid and loans from Russia for his impoverished Central Asian nation.

President Barack Obama’s calls for an increased military focus on Afghanistan could be hampered by the closure of the base.

The United States began using the Manas base shortly after it launched operations against Afghanistan for sheltering al-Qaida following the Sept. 11, 2001, attacks.