Britain hailed Pakistan's help in thwarting the planned attack, but the arrests on Pakistani soil showed that despite its successes against al-Qaida, the country remains a fertile ground for Islamic militancy.

British authorities arrested 24 people Thursday in what they said was a scheme to bring down as many as 10 jetliners in a nearly simultaneous strike. The suspects were believed to be mainly British Muslims, at least some of Pakistani ancestry.

The Foreign Ministry said that acting on information received from Britain, Pakistan had made arrests that triggered the arrests in Britain. It named British national Rashid Rauf as a "key person" who had been nabbed in Pakistan.

Interior Minister Aftab Khan Sherpao alleged that Rauf has ties with the al-Qaida terror network.

"We arrested him from the border area and on his disclosure we shared the information with British authorities, which led to further arrests in Britain," the interior minister told The Associated Press.

Foreign Minister Khursheed Kasuri, in an interview with CNN, confirmed the arrests of seven suspects in Pakistan, including Britons. He said the suspects "had been monitored for quite some time" before they were arrested.

Another senior government official said they included two Britons of Pakistani origin who were arrested about a week ago, and five Pakistanis detained in the eastern city of Lahore and the southern city of Karachi. The Pakistanis were arrested on suspicion that they served as the Britons' local facilitators, the official said.

An official at the British High Commission in Islamabad said he could not confirm the arrests of any Britons in Pakistan.

A Pakistani intelligence official said 10 Pakistanis were arrested Friday in Bhawalpur district, 300 miles southwest of Islamabad, in connection with the terror plot. A second intelligence official confirmed there were arrests in Bhawalpur, but did not know how many. The officials spoke on condition of anonymity because of the secretive nature of their jobs.

A Foreign Ministry statement said the arrests in Pakistan underscored "the very important role that has been played by Pakistan in breaking this international terrorist network." It said there were "indications of an

Afghanistan-based al-Qaida connection," but offered no details or supporting evidence.

Pakistan, a key ally of Britain and the U.S. in the war on terrorism, has been long been regarded as a center of Islamic militancy, much of it linked to events in Afghanistan. Since the Sept. 11 attacks on the United State, Pakistan has captured hundreds of al-Qaida fighters and arrested key figures in Osama bin Laden's terror network.

Talat Masood, a former Pakistani general, said the developments show that officials are cooperating in the war on terror, but also send another message.

"It has pluses and minuses. The minuses are that it shows many active terrorists have links with Pakistan and people are visiting Pakistan for this purpose," Masood said.

Three of the four suicide attackers in the deadly July 7, 2005, bombings on the London transport system were British Muslims of Pakistani origin and had visited Pakistan before the attacks.

One bomber visited a seminary run by a hard-line Islamic group, but officials in Islamabad say none of the bombers received militant training or support during their visits.