TASHKENT, Uzbekistan (AP) -- The Uzbek Senate on Friday endorsed the government's decision to evict U.S. troops from an airbase that has been an important hub for American military operations in Afghanistan.

Uzbekistan's ties with Washington have deteriorated since the Bush administration joined other nations in urging an international investigation into the suppression of a May uprising in the eastern Uzbek city of Andijan.

Uzbekistan's president, Islam Karimov, who has ruled the Central Asian nation for 16 years and tolerates no dissent, blamed the violence on Islamic militants.

He has rejected the demands for an outside inquiry, and, facing Western criticism, has found a strong support in Russia and China. Both of them are wary about the U.S. military presence in the strategic and resource-rich region.

The 93 Senators present at the session voted unanimously to support the July 29 order from Karimov's government giving the United States six months to vacate Karshi-Khanabad, an airbase in the southern Kashkadarya region.

No further action is necessary from the lower chamber, as the government-loyal, 100-seat upper chamber has the final say on parliamentary decisions.

The vote was not necessary to confirm the government's order. Rather it was seen as an attempt to give that ruling a symbolic show of popular support and legitimize it in the eyes of the international community.

''We know that fundamentalist moods arise wherever U.S. bases appear. Enemies of the United States appear wherever there is a U.S. military presence, and we don't want to be caught in-between,'' Kashkadarya governor Nuritdin Zainiyev said before the vote.

The head of the Senate's foreign relations committee and the country's former foreign minister, Sadyk Safayev, said the people of Kashkadarya had demanded the troops leave, alleging they had caused environmental damage. He also questioned the need for the troops in Afghanistan.

Uzbekistan issued the demand for the U.S. withdrawal just hours after hundreds of Uzbeks who had fled to Kyrgyzstan after the Andijan uprising were relocated to Romania, a staunch U.S. ally, by the United Nations refugee agency.

''If the U.S. is a friendly country ... how could they prevent the return of Uzbek refugees from Kyrgyzstan?'' Senator Surayo Abdukhojayeva demanded.

The United States and other Western countries harshly criticized Uzbekistan for using force against mostly unarmed civilians in Andijan on May 13. Rights groups said up to 750 people died in the crackdown. The government put the death toll at 187.

Zainiyev also complained that Uzbekistan had spent $160 million to maintain the infrastructure of the Karshi-Khanabad base since the arrival of U.S. troops, and the U.S. ''didn't pay anything.''

The base has been an important staging point for U.S. military operations in Afghanistan since the earliest days of the war, which began in October 2001. More recently, the base has been used to move supplies, including humanitarian aid, into northern Afghanistan. It also is a refueling point for transport planes.