Defense Secretary Donald H. Rumsfeld urged countries in Central Asia to "make up their own minds" about allowing U.S. military bases to remain in the region, despite recent pressure from Russia and China for a withdrawal deadline.

"We have a good arrangement in this part of the world -- arrangements plural," Rumsfeld told reporters on the flight to Bishkek, the capital of Kyrgyzstan. "The arrangements work well for us. They've been a great help to Afghanistan. They've been a great help with respect to the global war on terror."

Rumsfeld's trip comes as the Pentagon faces the biggest challenge to keeping bases in Central Asia since the fall of 2001, when it hastily negotiated access here to support the war in Afghanistan. The U.S. regional presence includes two key air bases that have handled tens of thousands of U.S. flights -- Ganci air base north of Bishkek, where 1,000 troops are stationed, and the Karshi-Khanabad air base in Uzbekistan -- as well as overflight rights, "gas and go" refueling agreements and emergency landing agreements.

On July 5, a summit of the Shanghai Cooperation Organization, made up of Russia, China and four Central Asian states -- Kyrgyzstan, Uzbekistan, Tajikistan and Kazakhstan -- called for setting a timetable for pulling out U.S. and other foreign forces, given what it described as the end of the "active military phase" of counterterrorist operations in Afghanistan.

But in meetings with Central Asian leaders this week, U.S. officials intend to dispute the view that the war in Afghanistan is winding down, according to a senior defense official traveling with Rumsfeld. "The basic premise that combat or anti-terrorist operations are complete in Afghanistan is flawed. It's not true," he said. Instead, continued U.S. military presence in the region will remain "vital" to combating the Taliban and terrorist groups such as al Qaeda, the Islamic Movement of Uzbekistan and affiliated splinter groups, he said.

In Kyrgyzstan, top government officials in recent days have softened their stance on the base at Ganci, playing down the timetable issue and privately indicating support for a continued presence, Western diplomats and officials in Bishkek said. Kyrgyzstan's newly elected president, Kurmanbek Bakiyev, came under pressure from Russia and Uzbekistan to sign the summit declaration, they said. Either country can cancel the basing agreement with 180 days' notice.

The U.S. military uses the airfield primarily for KC-135 refueling jets, as well as for C-130s that haul cargo and rotate troops, and pays commercial rates for jet fuel, parking space and landing slots, said a Western diplomat who spoke on condition of anonymity in anticipation of Rumsfeld's meetings with Bakiyev and the defense minister. The U.S. base employs 200 Kyrgyz citizens and generates income estimated at 3 percent of Kyrgyzstan's gross domestic product, the diplomat said.

Uzbekistan, in contrast, has moved closer to curtailing U.S. military access. "It's a growing concern," said the senior defense official. Uzbekistan has limited U.S. cargo flights and canceled night flights from Karshi-Khanabad since the spring, when relations with the Bush administration soured over the killing of hundreds of civilians by Uzbek soldiers during unrest in the city of Andijan in May.

Still, Rumsfeld and other Pentagon officials indicated they were looking for solutions to keep the U.S. military in Uzbekistan.

"We're not at that point" of seeking alternatives elsewhere, Rumsfeld said. But he indicated that the United States did have other options. "We always think ahead. We'll be fine," he said.

Russia and China have lobbied for a U.S. withdrawal from the strategic region on their peripheries, leading a top U.S. general last week to accuse them of trying to "bully" Central Asian nations. "That's their opinion," Rumsfeld said, referring to statements by Russia and China at the summit. "I think each country in the region, however, will make up their own minds as to what their relationships with others will be."

Russia has long-term bases in Tajikistan and Kyrgyzstan, where it signed a 15-year renewable contract in 2003 to station an air wing at a former Soviet base at Kant. A Russian delegation last spring also discussed with local officials establishing a second base in the southern Kyrgyz city of Osh.