"The government of Kyrgyzstan has taken its final decision about the closure of the American airbase," government spokesman Aibek Sultangaziev said.

"The issue is now with parliament which must cancel the agreement on the base with the United States. The Kyrgyz foreign ministry is exchanging views with the U.S. embassy on the time-frame for the base's closure."

The U.S. military base at Manas - used by coalition forces to support tens of thousands of troops in neighboring Afghanistan - is considered vital and U.S. reaction to the closure has been decidedly negative.

U.S. Secretary of State Hillary Clinton called the decision "regrettable" on Thursday but said U.S. operations in the region would continue to be effective, no matter what happened. "With respect to the base, the defense department is conducting an examination into how else we would proceed," Clinton told reporters after talks with French Foreign Minister Bernard Kouchner.

"It will not affect whatever decisions we make. It is regrettable. This is under consideration by the government of Kyrgyzstan and we hope to have further discussions with them."

The Manas base, operated by about 1,000 troops including small French and Spanish contingents, was set up to support coalition forces fighting to oust the Taliban regime in Afghanistan.

The closure of the base would strain U.S. supply lines at a time when U.S. President Barack Obama is preparing to nearly double the 36,000-strong force in the country.

The closure was announced Tuesday, after the Kremlin announced US$330 million in aid and debt relief as well as a loan worth US$2 billion for the impoverished Central Asian state. Kyrgyzstan has denied that the decision to close the base was connected to the loans from Moscow.

Kyrgyz Prime Minister Igor Chudanov expressed frustration that an agreement which "was signed for one year has now gone on for eight."