Although the lawmakers cited health, environmental and financial concerns, the move is widely seen as part of a backlash against Washington's criticism of the Central Asian nation's human rights record.
The Senate approval was not unexpected, said Kirill Nourzhanov, a Central Asia specialist at the Australian National University, as the 100-seat upper chamber is overwhelmingly loyal to President Islam Karimov.
"It's an absolute rubber stamp, even worse than the lower house of parliament," he said Monday. "It's a joke."
Washington and Tashkent signed an agreement in Oct. 2001, allowing the U.S. to use the Soviet-era Karshi-Khanabad airbase in the south of the country. America at the time was preparing to launch its military campaign against the Taliban militia and al-Qaeda allies in neighboring Afghanistan, following 9/11.
The resolution agreed upon Friday said the Senate saw no reason for retaining the agreement as "the period of war and conduction of large-scale military operations in Afghanistan has generally been concluded."
The measure also included one major complaint - that the U.S. had not paid for infrastructure work or to compensate those living near the airbase for harm caused to their health, or for damage to the environment.
During a debate on the resolution, lawmakers said Uzbekistan had spent $168 million for the infrastructure at the base -- known by the U.S. military as K-2 -- but had received nothing from the U.S.
Some also raised concerns about health problems allegedly experienced by the local population, and about the base "spoiling the environment."
But despite assertions by several lawmakers that the decision had nothing to do with American criticism of the government's actions -- in particular over a violent military clampdown on protestors in the town of Andijan last March -- political reasons for the decision were evident.
"A man with two faces cannot be a friend of Uzbekistan," Muriddin Zayniddinov, a senator from the region where K-2 is located, said in an address.
Although Washington has in the past raised human rights violations with Uzbekistan, Karimov was incensed when the U.S. backed calls for an international investigation into the events in Andijan.
Human rights groups believe up to 750 people died in the crackdown, while the government put the death toll at 187. Uzbekistan grumbled about a possible Western hand behind the protests, which came after political transitions -- "colored revolutions" -- in Kyrgyzstan, Ukraine and Georgia.
Karimov reacted to the U.S. criticism first by restricting flights in and out of the base, then by launching a stinging attack during a July 5 summit of a regional bloc, the Shanghai Cooperation Organization (SCO), complaining that outside forces were attempting to "hijack stability" in Central Asia.
The SCO, comprising four Central Asian republics as well as Russia and China, ended that summit by calling on the U.S. to set a timetable for withdrawing its forces from the region.
Three weeks later, Karimov formally gave the U.S. 180 days to vacate K-2, a decision now endorsed by the Senate.
Nourzhanov said the resolution was clearly directly linked to unhappiness over the U.S. stance on Andijan, and the "litany" of other reasons given by senators were "absolute rubbish."
"Uzbekistan was by far the largest recipient of American aid in the wake of [9/11]," he said, with funding "running into hundreds of millions of dollars."
"The financial argument is totally spurious -- Uzbekistan did not make a financial loss by keeping the American base on its territory."
As far as the health and environmental problems were concerned, Nourzhanov said, no evidence was presented.
"Medically, has it been established that noise produced by planes or exhaust [fumes] have somehow contributed to these problems? I don't know. And since when are the Uzbek authorities caring about the well-being of their own population?"
The reasons cited by the lawmakers, he said, appeared to be an attempt "to camouflage the real dynamics behind the decision."
Following the SCO resolution, Defense Secretary Donald Rumsfeld visited the region, making stops in two Central Asian members of the bloc, Kyrgyzstan and Tajikistan, while skipping Uzbekistan.
During that trip, Rumsfeld secured approval from Kyrgyzstan to continue using the Manas airbase there, and from Tajikistan to maintain overflight and refueling rights for U.S. aircraft.
At the time he seemed untroubled about the threat to the K-2 base, saying in response to a question "We're always thinking ahead ... we'll be fine."
Pentagon spokesman Lawrence DiRita said early this month the U.S. was considering other alternatives in the region, and the U.S. Ambassador to Kyrgyzstan, Stephen Young, subsequently told a news conference some duties were being transferred from K-2 to Manas.
Last week, U.S. Central Command chief Gen. John Abizaid another regional country, Turkmenistan, for talks with senior political and military figures.
No cooperation decisions were announced, but the U.S. Embassy in the capital, Ashgabat, said in a statement Abizaid and President Saparmurat Niyazov "discussed areas of mutual interest, including broad security issues of regional consequence."
Abizaid had also reassured Niyazov that the U.S. presence in the region was "to stabilize Afghanistan, not to seek confrontation with any of the nations in the region," it said.
The K-2 base was particularly prized because of its location near Uzbekistan's border with Afghanistan. Kyrgyzstan does not border Afghanistan - Tajikistan is located between the two - which is why overflight rights with the latter were required.
Turkmenistan is strategically located, bordering both Afghanistan and Iran. But its government is also the most authoritarian in Central Asia, with no independent political activity or opposition parties allowed, and press and religious freedom curtailed.
Nourzhanov said despite speculation that the U.S. may be looking for a temporary base there, "I don't think that's likely because Turkmenistan is a prime candidate for another 'colored revolution' - it's much more unstable than Uzbekistan."
He also questioned the continuing importance of a base in Uzbekistan, arguing that the key U.S. bases in Afghanistan itself, Bagram and Shindand, had reportedly been renovated sufficiently to enable aircraft of any type to land there.
Bagram is north of Kabul, while Shindand lies south of the western city of Heart, towards the border with Iran.
See earlier story:
Central Asian Republics Say US Forces Can Stay (Jul. 27, 2005)
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