The US military on Wednesday faced the prospect of a costly logistical headache trying to move troops and supplies into Afghanistan, after Kyrgyzstan moved to close a major US air base that served as a vital hub.

The closure would place a strain on US supply lines at a time when President Barack Obama is preparing to nearly double the 36,000-strong force in the country and amid increasing attacks on supply routes through Pakistan.

About 15,000 people and 500 tonnes of cargo move in and out of the Manas air base every month supporting the NATO force in Afghanistan as well as the Afghan army, the Defense Department said on Wednesday.

"It''s of concern but it''s certainly not a disaster," William Nash, a retired Army general, told AFP.

Nash said there were some "potential sites around the area" and that it was likely that the United States would be able to use bases or roads elsewhere in Central Asia.

The Kyrgyzstan base remains the only US outpost in Central Asia after the US military was evicted from Uzbekistan in 2005 following Washington''s condemnation of Tashkent over human rights violations.

But the Pentagon on Wednesday played down the impact of losing use of the Kyrgyz base, saying it would not in anyway undermine the military''s operations in Afghanistan.

"The United States would certainly be able to continue operations in Afghanistan if we did not have that facility," Pentagon spokesman Bryan Whitman said.

"We are talking about the United States military, the most flexible, adaptable, capable, innovative military in the world," he said.