U.S. Defense Secretary Robert Gates says Kyrgyzstan's decision to shutter an American air base is not a "closed issue."
The comments came Friday after Kyrgyzstan ordered U.S. forces to leave within six months from the air base key to U.S. and NATO operations in Afghanistan, AP reported.
The move complicates U.S. plans to send more troops to battle rising Taliban and al-Qaida violence.
The Kyrgyz Foreign Ministry says it sent a formal notification of the closure of the Manas base to the U.S. Embassy on Friday. U.S. troops now have 180 days to leave.
Kyrgyzstan complained the United States was not paying enough rent, though Gates has offered to review the amount. U.S. officials suspect Russia is behind an effort to push the Americans out of Central Asia.