"I can confirm that our embassy in Tashkent received a diplomatic note from the Uzbek government late last week to terminate the agreement for use of the K-2 air field," Nancy Beck, a spokeswoman for the State Department, said on Saturday.
"This is a bilateral agreement between two sovereign nations and under that agreement, either side has the option to terminate the agreement," Beck said, adding that she had no more details on the development.
The Washington Post had reported earlier in the day that a courier from the Uzbek Foreign Ministry delivered a notice of the eviction from Karshi-Khanabad air base, known as K2, to the US Embassy in Tashkent on Friday.
Uzbekistan will give the United States 180 days to move aircraft, personnel and equipment, according to the report, which cited unnamed State Department and Pentagon officials.
Critical staging point
K2 has been a critical staging point for US military operations in Afghanistan since the earliest days of the American-led invasion, which began in October 2001.
Karshi-Khanabad has been a landing base to transfer humanitarian goods that are then taken by road into northern Afghanistan, particularly to Mazar-i-Sharif - with no alternative for a region difficult to reach in the winter, the report said.
"I can confirm that our embassy in Tashkent received a diplomatic note from the Uzbek government late last week to terminate the agreement for use of the K-2 air field"
US State Department spokeswoman
K2 is also a refuelling base with a runway long enough for large military aircraft, the paper pointed out.
The Post quotes Pentagon spokesman Lawrence Di Rita as saying the US military does not depend on one base in any part of the world.
"We'll be able to conduct our operations as we need to, regardless of how this turns out. It's a diplomatic issue at the moment," Di Rita said.
The eviction notice came four days before a senior State Department official was to arrive in Tashkent for talks with the government of President Islam Karimov, The Post reported.
Defence Secretary Donald Rumsfeld visited Central Asia this past week, where he inspected US bases in Kyrgyzstan and Tajikistan.
During his trip, Rumsfeld said he did not believe US operations in Afghanistan would be hurt if the Uzbek government denied continued use of K2 because there are other air base options in the region.
Rumsfeld (L) visited Kyrgyz
leader Kurmanbek Bakiyev (R)
"We're always thinking ahead. We'll be fine," Rusmfeld said on Monday.
In early July, a regional organisation led by Russia and China issued a statement calling for the US to set a timetable for withdrawing its forces from Uzbekistan and Kyrgyzstan.
Tensions in Washington's relations with Kyrgyzstan and other Central Asian nations stem partly from an eruption of violence in mid-May in the Uzbek city of Andijan.