WASHINGTON - The United States is considering resuming military cooperation with authoritarian Uzbekistan as a part of backup planning for the potential loss of a nearby air hub for troops and supplies in the widening Afghanistan war, U.S. officials said yesterday.

Defense officials say they are examining options for supply routes through a semicircle of nations from Central Asia to the Persian Gulf that could be used in place of the strategic air base in the former Soviet republic of Kyrgyzstan.

Uzbekistan, a hard-line former Soviet satellite with rigid economic controls, is a surprise contender because diplomatic relations between the United States and Uzbekistan are rocky at best. After a brief 1990s rapprochement, the Uzbeks expelled American forces from a base there in 2005, and the two nations have traded accusations ever since.

Defense officials said planning to substitute for the Manas base was a preliminary hedge in case that government made good on a threat to expel the United States from the hub serving about 15,000 U.S. personnel coming and going from Afghanistan each month, along with 500 tons of goods.

Defense officials spoke on condition of anonymity because the plans are preliminary and the United States is still negotiating with Kyrgyzstan about continued use of the base.

Several officials said that dispute was likely to come down to money: Either the United States agrees to a significant increase in rent, or Kyrgyzstan will yield to Russian pressure to kick out the United States.

Asked about the Kyrgyz situation in an appearance at the State Department, Secretary of State Hillary Rodham Clinton said it was troubling but would not impede U.S. plans to expand its military presence in Afghanistan. She said the Pentagon was "conducting an examination as to how else we would proceed" in the event the Manas base was no longer available.

"It's regrettable that this is under consideration by the government of Kyrgyzstan," Clinton said. ". . . But we will proceed in a very effective manner no matter what the outcome of the Kyrgyzstan government's deliberations might be."