U.S. and Pakistani intelligence experts questioned a suspected high-ranking Al Qaeda lieutenant Sunday, hoping to zero in on the whereabouts of Usama bin Laden.

Yassir al-Jaziri, arrested Saturday, was allegedly responsible for communications among Al Qaeda leaders. Investigators hope he can tell them more about where bin Laden and other top Al Qaeda leaders may be hiding in Afghanistan or Pakistan and more about how they operate, said Pakistani security sources familiar with the interrogation.

"Al-Jaziri is definitely an important Al Qaeda leader," Interior Secretary Tasneem Noorani told The Associated Press. "We understand that he is among those Al Qaeda leaders wanted by the United States."

Al-Jaziri, who was apprehended in the eastern city of Lahore, has told investigators that the last time he conveyed a message to bin Laden was "four or five months ago," the Pakistani sources said. He has not admitted having a direct meeting with bin Laden, they added.

He was removed from Lahore for questioning following his arrest by Pakistani authorities, officials said. Information Minister Sheikh Rashid Ahmed told The Associated Press that al-Jaziri was being interrogated at an undisclosed location in Pakistan.

Investigators hope to build on information they gathered from other recent arrests. The capture of al-Jaziri was made possible by information gleaned from Khalid Shaikh Mohammed, the alleged mastermind of the Sept. 11 attacks, Ahmed said.

Mohammed, Al Qaeda's suspected No. 3, was arrested March 1 in Rawalpindi, near the capital Islamabad. Mohammed's arrest was the most significant catch since the U.S.-led war on terror began in October 2001.

Intelligence officials said Afghan national Gul Zeb -- arrested with al-Jaziri -- also was being questioned but was regarded as less important. Al-Jaziri is among the two dozen most-wanted figures in Al Qaeda, U.S. sources said on condition of anonymity, but he is not on the FBI's most-wanted list.

Al-Jaziri's name emerged last January.

Prosecutor Sher Zaman said he was an Al Qaeda terrorist who had been in contact with Dr. Ahmad Javed Khawaja, a naturalized U.S. citizen who lives Lahore, and eight of the doctor's relatives who were arrested in December on charges of harboring Al Qaeda operatives. Some of his relatives have been released.

One of his brothers said Sunday that no one had questioned the family about al-Jaziri or his arrest.

"We know nothing about al-Jaziri," said Ahmad Nadeem Khawaja, who was detained and released last December. "And as for the allegation that we harbored him, it's a pack of lies."

Pakistani officials said the Americans gave them information on al-Jaziri's location last week, but U.S. agents did not participate in his capture, U.S. and Pakistani sources said.

Court documents describe al-Jaziri as an Algerian-Moroccan dual national responsible for Al Qaeda's business interests.

Intelligence sources said documents, compact discs and a computer were found at the home where al-Jaziri was arrested. Their content was not immediately known. The Pakistani family he had been staying with was being interrogated but not under arrest.

Ahmed did not rule out turning al-Jaziri over to U.S. authorities quickly if a request was made.

Pakistani police and U.S. Special Forces have been combing the Afghan border and the mountains of eastern and southwestern Afghanistan for fugitive Al Qaeda operatives, but the major arrests have been made in Pakistani cities. Mustafa al-Hisawi, a suspected financier of the Sept. 11 attacks, was arrested with Mohammed.