U.S. warplanes again struck a suspected Al Qaeda base in eastern Afghanistan Friday after coalition observers detected some terrorist network fighters trying to reassemble there, military officials said. 

The second day of bombing on the Zawar Kili camp near Khowst took place in the late morning on Friday, after coalition forces observed some activity at the base in the hours following the first strike, Pentagon spokewoman Victoria Clarke said Friday morning.

Pentagon officials have said they worry remaining Al Qaeda members may be attempting to regroup at the base. Thursday's strike marked the first U.S. bombing of the new year.

The search for Al Qaeda leader Usama bin Laden, whom the United States holds responsible for the Sept. 11 terrorist attacks, continues by land, sea and air.

Defense Secretary Donald H. Rumsfeld said the Pentagon will continue pursuing bin Laden and his top lieutenants, as well as Mullah Mohammed Omar and other Taliban leaders. The military campaign in Afghanistan will not be over until they are found, Rumsfeld said.

"We intend to find them and we intend to capture or kill them," Rumsfeld told a Pentagon news conference Thursday.

"Our real goal is to see that people are not committing terrorist acts," he added later.

Rumsfeld repeatedly said the U.S. military campaign against Al Qaeda has been effective, even while acknowledging that it has not met President Bush's stated goal of bringing top terrorist leaders to justice.

Rumsfeld said the military campaign has made it harder for Al Qaeda to raise money, to communicate among its members, to travel inside and outside Afghanistan, and to train its members in terrorist techniques.

"We've disrupted any number of training camps, and it does take training to become a polished, successful murderer or mass murderer," Rumsfeld said. "You just don't walk out of grade school with that kind of knowledge; you need to practice and be taught by experts."

Details of the strikes on Thursday and Friday were sketchy. In the first strike, defense officials said four B-1B aircraft and three F/A-18s dropped about 100 bombs on the compound, which included a training facility and a cave complex. Also taking part was at least one AC-130, a special operations aircraft that delivers a withering barrage of cannon fire and howitzer shells. F/A-18s and other planes conducted the second strike, Clarke said.

An official who spoke on condition of anonymity said the undetermined number of Al Qaeda fighters at the compound appeared to be regrouping either to resume fighting or to slip across the nearby border into Pakistan.

U.S. cruise missiles struck the same compound in August 1998 in response to terrorist attacks on U.S. embassies in Africa, Myers said. It also was struck in November.

"It has been a place where the Al Qaeda goes to regroup," said Gen. Richard Myers, the chairman of the Joint Chiefs of Staff. It was not clear how many Al Qaeda members may have been killed in the attack.

On Wednesday the Pentagon said its concern about Al Qaeda members regrouping — after having abandoned their last major stronghold in the mountainous Tora Bora region north of Khowst — led to air strikes Dec. 28 on a compound near the city of Gardez, a short distance from the site of Thursday's bombing.

In other developments:

—Afghan officials said they were trying to get tribal leaders to surrender their weapons as they continued to search the mountains for Omar. U.S. officials were insistent that no deal be offered that would lead to freedom for Omar, the second most wanted man after bin Laden.

—Prime Minister Hamid Karzai has agreed to visit President Bush next month in what will be the first visit to Washington by an Afghan leader in almost 40 years, the White House said.

—Pakistan arrested the former Taliban ambassador in Islamabad, Mullah Abdul Salam Zaeef, said Zaeef's nephew, Hamid Ullah. He said he did not know the reason for the arrest of Zaeef, who was the most prominent Taliban spokesman during the U.S. campaign against the militia.

—Clarke said the United States is currently holding 273 Taliban or Al Qaeda members from Afghanistan either at U.S. bases in the country or on ships. Rumsfeld said an undetermined number of prisoners would be moved to the U.S. Navy base at Guantanamo Bay, Cuba, as soon as the base is readied.

Rumsfeld also said some military bases in the United States could be used to house prisoners captured in the anti-terrorism campaign.

The Pentagon told staff of Sen. Ernest Hollings, D-S.C., that a brig at the Charleston Naval Weapons Station in South Carolina could be used to house prisoners detained in the United States who are to be tried by a military tribunal, according to a Hollings spokesman, Andy Davis.

The Associated Press contributed to this report.