Uzbekistan has called for the removal of U.S. military aircraft and personnel from a base that is key to operations in neighboring Afghanistan, U.S. officials said yesterday.

There was no official answer to what prompted the decision, although U.S. authorities tied it to tensions related to the iron-fisted response by the government of Uzbek President Islam Karimov to anti-government protests in May.
Hundreds of protesters are believed to have been killed by government security forces.

The government served notice that the United States will have to leave the Karshi-Khanabad air base within six months.

The government's decision followed a trip last week by Defense Secretary Donald H. Rumsfeld to two of Uzbekistan's Central Asian neighbors, Kyrgyzstan and Tajikistan. During the trip, Mr. Rumsfeld received assurances from officials in both nations that U.S. forces can continue to use bases there.

Mr. Rumsfeld did not visit Uzbekistan, and Pentagon spokesman Bryan Whitman said yesterday that the Defense Department is now "in consultation with the State Department to determine what the future might hold there."
"This is a bilateral agreement between two sovereign nations, and under that agreement, either side has the option to terminate that agreement," State Department spokesman Nancy Beck said yesterday.

Pressure has been mounting from the international community for an independent probe into Uzbekistan's handling of the May protests. Mr. Karimov, a near-absolute ruler in power for 16 years, blames the clashes on Islamic militants and has rejected calls for an outside investigation.

One U.S. official told The Washington Times yesterday that the United States has been "re-evaluating whether this is a place we want to work out of, since they're not being transparent in their investigation."

The demonstrations erupted in the eastern Uzbek city of Andijan, where the government has conducted continual crackdowns on Islamic groups. Andijan is in an enclave near the border with Kyrgyzstan, where protests toppled the Kyrgyz government in March.

On Thursday, the United Nations High Commission on Refugees announced that Romania had agreed to take in 455 Uzbek refugees who had fled from the government crackdown after the protests.

The New York Times reported yesterday that senior State Department officials said Uzbekistan delivered the base eviction notice to protest the U.N.'s efforts to assist those who had fled the uprising.

U.S. defense officials insist they will be able to adjust operations without use of the base in Uzbekistan, commonly called "K2" and located about 90 miles north of the border with Afghanistan, but the development is a blow to the Pentagon because the base is central to operations in Afghanistan.

K2 is "critical to our ability to conduct combat operations against the Taliban and al Qaeda and also to our effort to deliver humanitarian assistance to northern areas of Afghanistan," Mr. Whitman said.

The operations "would certainly be more difficult and more costly" if U.S. forces no longer are allowed to use the base, he said, but "our operations are not dependent on this or any other single facility" in Central Asia, Mr. Whitman added.

"We plan for any number of situations out there. We're capable of adapting," he said.

This article is based in part on wire reports.