Washington ? A senior al-Qaida leader was recently taken into U.S. custody overseas, officials said Friday. They declined to identify him.

The officials, speaking on condition of anonymity, ruled out three of al-Qaida’s most wanted: Osama bin Laden himself, his chief deputy, Ayman al-Zawahiri, and suspected Sept. 11 mastermind Khalid Shaikh Mohammed.

They also said bin Laden’s son, Saad, another al-Qaida leader, was not among the captured.

Since the Sept. 11 attacks, the CIA, FBI and military have been making slow but steady progress in catching or killing the people they have identified as bin Laden’s top lieutenants.

But a number of senior operatives with ties to Sept. 11, the USS Cole bombing in October 2000, the 1998 U.S. Embassy bombings in Africa and other attacks remain at large.

Sen. Richard Shelby, R-Ala., vice chairman of the Senate Intelligence Committee, would not confirm that a new leader was in custody.

“When there is an arrest of a leader, it gives us opportunities,” Shelby said. “At least it shows we’re on top of things and we’re going after the al-Qaida group and their affiliates and their associates wherever they are in the world.”

On Nov. 3, the CIA killed bin Laden’s top operative in Yemen, Qaed Salim Sinan al-Harethi, in a missile strike launched from an unmanned Predator aircraft.

On the anniversary of the Sept. 11 attacks, U.S. and Pakistan authorities captured Ramzi Binalshibh, another alleged planner of the strikes on the World Trade Center and Pentagon, in Karachi.

In March, CIA, FBI and Pakistani operatives captured Abu Zubaydah, a senior al-Qaida terrorist operations planner with worldwide connections. His associate Abu Zubair al-Haili was taken in Morocco in June.

Mohammed Atef, bin Laden’s top deputy and operations planner, was killed in a U.S. airstrike in Kabul last November.