London ? Investigators have identified the leader of an alleged terrorist cell broken up by police here 10 days ago and have traced his contacts to Pakistan, where U.S., British and Pakistani intelligence agents are pursuing the man’s suspected connections with al-Qaida.

The man, Ali Ahmed Khan, who was taken into custody with other purported cell members but whose name has not been made public, was acting as the chief “facilitator” of an alleged plot to bomb several trans-Atlantic airliners headed for the United States, according to a U.S. intelligence official.

The official, who spoke on condition of anonymity, compared Khan to Mohamed Atta, the Egyptian university student who, acting on instructions from top-ranking al-Qaida members in Afghanistan, organized the 9-11 hijacking plot that killed more than 3,000 people.

“He is a cell leader in Britain,” the U.S. official said.

The question the authorities are trying to answer, he said, is: “How strong an al-Qaida affiliation does he have?”

The U.S. official said Khan, about whom little is known, had been taking directions from Rashid Rauf, a dual Pakistani-British citizen who was arrested in Pakistan shortly before British police rounded up Khan and 23 other British residents believed to be members of Khan’s cell. Days later, a 25th person was arrested in Britain. Two of those arrested have since been released.

Pakistan authorities now believe that a ranking al-Qaida leader in Afghanistan hatched the plan, said a top Pakistani government official who spoke on condition of anonymity because of British requests that he not talk about the case. Afghan officials have denied that the plot came from their country.

Some terrorism experts have expressed caution about whether there is a definite link to al-Qaida.

Rauf, 29, was either responsible for the planning of the attack or acted as the liaison between al-Qaida in Afghanistan and planners in Britain, according to the Pakistani government official.

Rauf’s arrest Aug. 9 in Bahawalpur in eastern Pakistan, a hotbed for Islamic militants, triggered the unraveling of the alleged plot and the arrest of the suspects in Britain, including Rauf’s brother, Tayib.

Rashid Rauf “is certainly a key figure – not a mastermind,” the Pakistani official said.

Since the arrests began, British police have launched an intense search for evidence, serving 46 search warrants.

The BBC reported Friday that 11 locations were still being searched.

Crime technicians in overalls and latex gloves have been picking through the modest homes of the suspects in the working-class northeastern London neighborhood of Walthamstow and suburban High Wycombe, west of the city.