The United States is no longer dropping bombs in Afghanistan and few Al Qaeda fighters have been captured in recent weeks. The country is stabilizing a bit, but the 7,000 American soldiers there won't be leaving any time soon.

One reason is the fear that if the troops left, Usama bin Laden's Al Qaeda fighters who fled across the border to Pakistan would go right back in, U.S. officials said.

What's more, the thousands of U.S. troops sent to countries surrounding Afghanistan -- such as Uzbekistan and Kyrgyzstan -- are digging in for the long haul, too.

In Afghanistan itself, U.S. combat troops are expected to remain at least one year more, and perhaps 18 months, the spokesman for the general in charge of operations said Wednesday.

For a Bush administration that often stresses the need to re-evaluate military missions and draw down troops when possible, the long and open-ended troop commitment in Afghanistan has been forced by circumstances, especially the difficulty of hunting elusive small groups of Al Qaeda, U.S. officials say.

"How long does it take to find these groups and convince them to stop their activities?" Col. Roger King, spokesman for Lt. Gen. Dan K. McNeill, asked Wednesday in Bagram, Afghanistan. "It might happen quickly, it might not."

The American troops are searching for an estimated 1,000 Al Qaeda and Taliban fighters believed still hiding in small groups in the country -- a difficult task that some liken to tricky Vietnam-era search and destroy missions.

They also are still uncovering caches of weapons, Gen. Richard B. Myers, chairman of the Joint Chiefs of Staff, said earlier this week.

The soldiers also are helping train a national Afghan army in the hope it eventually will be able to prevent warlords from plunging the country into a new round of fighting.

Other U.S. soldiers are performing support tasks, like security at the Kandahar and Bagram bases. Air patrols continue to fly, looking for targets, but few U.S. bombs have been dropped since the Anaconda operation in early spring. Even during that operation, U.S. bombing runs were much less intense than during the main U.S.-led bombing that tapered off at the end of December.

Much of what U.S. troops are doing remains secret, said John Pike, a defense analyst at Globalsecurity.org in Washington. A rash of reports of U.S. special forces raids on suspected Al Qaeda, who turned out to be innocent bystanders, has faded somewhat from mid-spring, he said.

"Either they're doing less, or their intelligence is better," Pike said. "And we have no way to gauge that."

Beyond the immediate goal of finding Al Qaeda, the U.S. troops are ensuring that Al Qaeda fighters don't return to Afghanistan from Pakistan, said retired Rear Adm. Stephen Baker, a defense analyst at the Center for Defense Information in Washington.

And, despite Bush administration dislike for peacekeeping operations, the soldiers are keeping Afghanistan stable so democratic institutions like a central government and schools can begin operating.

"The Afghans are clearly taking charge of their own destiny," Baker said, citing the selection of president Hamid Karzai and a cabinet by a grand council, or loya jirga, this week.

"But it takes time," Baker said, "and there's a clear value to the American troops there as a stabilizing influence."

Even as the United States commits to a year or more, some allies are pulling back troops.

British officials this week will announce the withdrawal of 1,700 Royal marines from Afghanistan. Britain also is scheduled to hand over leadership of the Kabul-based peacekeeping force to Turkey later this week.

Canada also has said it will bring home its 800 ground troops this summer, ending a six-month mission. But Germany voted to extend its participation of 1,000 troops through December, and Turkey will commit 1,500 troops altogether to the Kabul peacekeeping force.

In other central Asian countries, meanwhile, the Pentagon is considering ways to keep some troops or equipment in the region even after U.S. forces leave Afghanistan, officials have said privately.

Before the United States launched the war in Afghanistan last October, it had no forces based in Central Asia. Now it has thousands, including about 1,000 in Uzbekistan and 1,000 in Kyrgyzstan.