Some military experts have said the development increases the strategic importance of the Bagram Air Field north of Kabul. U.S. military engineers have been building up the infrastructure at Bagram for more than three years. They say the clearing of unexploded ordnance and the expansion of runway space at Bagram during the past 18 months could allow that facility to be used more extensively when the last U.S. soldiers leave K-2.
A report by "The Washington Post" newspaper says Uzbekistan will give the United States six months to move its aircraft, personnel, and equipment. Neither the Pentagon nor the State Department would comment on the reported timeline.
James O'Halloran, editor of the annual publication "Jane's Land Based Air Defence" and owner of the British-based firm Research Analyst Defense, said the closure could have significant impact on the way U.S. forces conduct and support combat and reconstruction operations in neighboring Afghanistan.
"The [K-2] airfield itself is a forward operating base [in the southern part of Uzbekistan] which, logistically, gives the U.S. a very good jumping off point into Afghanistan when it needs to move troops and logistics in that area," O'Halloran said.
Defense Department spokesman Glenn Flood said the U.S. military is working with the State Department to determine exactly what the note means for U.S. strategic interests in Central Asia. The White House declined immediate comment.
Flood suggested that the action could create logistical problems for U.S. military operations in Afghanistan as well as humanitarian relief workers in the region.
Washington has signaled in the past that it considers its bases in Uzbekistan and Kyrgyzstan as vital for operations in Afghanistan. But U.S. presence in Central Asia has caused tensions with Russia and China, which joined the five ex-Soviet Central Asian states this month to demand a deadline for leaving the bases.
O'Halloran said Tashkent's decision does not come as a surprise.
"I believe that the U.S. has expected to lose the K-2 base for some time now as political pressure has been applied through various sources to hold back the U.S. expansion, shall we say, into the former Soviet empire," he said. "A lot of people are saying that [the United States is] expanding a little too quickly now. They're over-stretching things. And I do believe it is politics which has forced the expected closure of K-2."
O'Halloran said he also thinks Russian President Vladimir Putin put political pressure on Uzbekistan to call for the U.S. withdrawal.
"There's no question that Moscow is involved in this and that Moscow is not comfortable with the U.S. expanding so closely to its borders and moving into the former Soviet empire," O'Halloran said. "I'm sure that Uzbekistan has accepted this from Mr. Putin, the president there, and in turn, has spoken to the U.S. about this -- and they've all agreed, politically, that this is probably a good move to make."
U.S. relations with Uzbekistan also have been strained by the Uzbek government's bloody suppression in May of a rebellion in the eastern Uzbek town of Andijon. That crackdown has drawn criticism from the United States. [For an RFE/RL archive of coverage of events in Andijon and the aftermath, click here.]
But O'Halloran said he does not think U.S. criticism played a significant role in Uzbekistan's decision.
"On the world scale of things, I don't think [the U.S. reaction to the Andijon crisis] played a major part in this," he said. "I think the politics coming out of Moscow probably has more to do with it than anything else."
"The New York Times" yesterday quoted one State Department official as saying that Uzbekistan's decision on K-2 is a response to a United Nations operation to take hundreds of Uzbek refugees from the region. Related statements have also been "highly critical of officials in Tashkent.
More than 400 people who fled to Kyrgyzstan after the May uprising were flown Friday to a refugee camp in Romania. The Uzbek government had sought their return.
U.S. Defense Secretary Donald Rumsfeld told reporters on 25 July that Tashkent and Washington still enjoy good relations.
Rumsfeld made the remarks during a visit to neighboring Kyrgyzstan. The Kyrgyz defense minister said the United States can keep a military presence in his country until stability returns to nearby Afghanistan.
Tajikistan also made a similar pledge during a recent visit there by Rumsfled. The Tajik government in Dushanbe has vowed to continue supporting international forces in Afghanistan.
Tajikistan has given U.S. planes refueling and overflight rights in conjunction with Afghanistan missions. Some 200 French air force personnel and two transport aircraft also are based at Dushanbe airport for Afghan operations.
(with additional wire reporting)
Central Asia: Is It Time To Withdraw U.S. Troops?
Is Regional Turbulence Return Of The Great Game?
SCO -- Shoring Up The Post-Soviet Status Quo
[For more on events in the region, see our dedicated Central Asia In Focus archive.]