Nearly four months into the hunt for Usama bin Laden, Defense Secretary Donald Rumsfeld on Thursday said the U.S. military will "complete the mission" in Afghanistan and pledged to bring the terrorist leader and his cohorts to justice.

"We are looking for them, we intend to find them, and we intend to capture or kill them, and that's the best we can do," Rumsfeld said at his first post-holiday Pentagon briefing.

"Our goal is to find them and we intend to pursue that," the Pentagon chief said at another point. "There is still a good deal of work to do in Afghanistan. We will complete the mission."

On Thursday, Air Force and Navy warplanes attacked a military compound south of Tora Bora, which included a terrorist training camp and caves near the Pakistan border. The site had been struck in 1998 by U.S. cruise missiles but Al Qaeda forces active were still active there, officials said.

Rumsfeld described the U.S. effort so far as successful, given that "Taliban rule in Afghanistan has ended, and that is a good thing ... good for Afghanistan, good for the world."

A new, interim government is in place that shares Washington's desire to rid Afghanistan of terrorists, he added. And although it has been difficult to find bin Laden, his terrorist network has been hobbled, Rumsfeld contended.

Gen. Richard Myers, chairman of the Joint Chiefs of Staff, who joined Rumsfeld at the briefing, said the effort has been "fruitful in stopping terrorist acts around the world," but he declined to offer any specific details because the operations are still under way.

Rumsfeld said the U.S. operation has disrupted terrorists' training camps, dried up portions of their financial networks, and helped make it "very, very difficult to conduct terrorist acts."

However, both men said the war against terrorism is far from over, and that the hunt for those held responsible for the Sept. 11 terrorist attacks against the United States will not end even if bin Laden and his top lieutenants are found.

"If we capture them tomorrow, our work would be far from over," Rumsfeld said.

Queried about reports of negotiations for the surrender of hundreds of Taliban fighters, including their supreme leader, Mullah Mohammad Omar, Rumsfeld said it is not his intention to authorize negotiations that will "let people go" who are being sought by Washington.

Rumsfeld said he the interim government in Afghanistan is "on the same sheet of music with us" about the final determination of such people. Myers said 248 detainees are under U.S. control in Afghanistan or aboard a Navy ship offshore.

The defense secretary said a detention center at Guantanamo naval base in Cuba is now under construction for potential use by the detainees and that great care is being taken to ensure there is no repeat of the unrest among detainees that resulted in the loss of a CIA operative in November.

"These are very hard cases," Rumsfeld said.