U.S. forces pulled a prominent tribal leader out of southern Afghanistan for consultations, not to rescue him, Defense Secretary Donald H. Rumsfeld said Tuesday.

Rumsfeld said Hamid Karzai, an exiled tribal chief who had been in Afghanistan to rally opposition to the Taliban, was flown to Pakistan, where he has been living in recent years. Rumsfeld said Karzai "undoubtedly" will go back to southern Afghanistan to resume his efforts against the Taliban.

"To my knowledge, he was not detained or held by the Taliban," Rumsfeld told a Pentagon news conference. "It was a very sensible arrangement whereby he requested to be extracted for a period, and we cooperated."

Whatever the circumstance of his departure, Karzai was one of two key opposition figures the United States has counted on to stir up trouble for the Taliban and to organize efforts to form a replacement government. The other, Abdul Haq, entered Afghanistan last month and was captured and executed by the Taliban.

Karzai and his band of armed supporters battled Taliban forces last week in the southern province of Uruzgan, with the two sides offering widely conflicting accounts of the fighting. The Taliban said members of Karzai's group were killed, and that Karzai was rescued by a U.S. helicopter.

Karzai's brother Ahmed confirmed the gunbattle, but said his brother and his men made it to safety.

Rumsfeld said Karzai was flown out of Afghanistan on Sunday with a small number of senior supporters and fighters. He said U.S. forces had been supplying ammunition to Karzai's fighters before the extraction.

President Bush, meanwhile, said the U.S. bombing campaign in Afghanistan has made good progress since it began Oct. 7, although he cautioned Americans not to expect it to end soon.

"We are at the beginning of our efforts in Afghanistan, and Afghanistan is the beginning of our efforts in the world," Bush said.

At his news conference, Rumsfeld said there was no telling how long it would take for anti-Taliban forces to succeed. American military assistance will continue, he said, but he declined to say whether he believed the alliance of opposition forces in northern Afghanistan would ultimately succeed.

"It is not going to be a steady march forward across a front. It is going to be probes and pushes and successes and steps back. That is the nature of it, and I think we just have to face that fact," he said.

On Capital Hill, Sen. John McCain, R-Ariz., a member of the Senate Armed Services Committee, said he was encouraged that U.S. bombing in recent days has focused on the Taliban's frontline troops.

"They've really been pounding very hard the Taliban lines. I think that's very good. I hope the northern alliance succeeds," he told reporters.

At the Pentagon, the vice chairman of the Joint Chiefs of Staff, Marine Corps Gen. Peter Pace, told reporters that U.S. forces recently began using a huge bomb known as a "daisy cutter." The 15,000-pound bomb is billed as the world's most powerful non-nuclear bomb, in terms of explosive power. Most bombs used by the United States range from 500 to 2,000 pounds, although the Air Force also has dropped a few 5,000-pound "bunker buster" bombs against underground targets.

Pace said the U.S. military has dropped two "daisy cutters," technically called the BLU-82, recently in Afghanistan. They are shoved out the back of an Air Force C-130 transport plane and float down by parachute.

"As you would expect, they make a heck of a bang when they go off, and the intent is to kill people," Pace said, adding that they are especially effective against troops in light defensive positions.

In keeping with the Pentagon's practice of discussing only the previous day's bombing activity, Pace said U.S. warplanes flew about 100 attack missions on Monday, mostly against Taliban troops and cave complexes.