LAHORE, Pakistan – Two of the London Tube bombers traveled together to Pakistan five months before their suicide attacks, immigration officials in Pakistan confirmed yesterday.

Pakistani investigators now believe that, contrary to initial reports, 22-year-old Shehzad Tanweer visited Pakistan five times in the last four years, staying for a total of seven months.

[In another development, Britain’s chief intelligence and law-enforcement officials said, less than a month before the tube bombings, that there was “not a group with both the current intent and the capability to attack the U.K.,” according to a report on the New York Times Web site last night.

The Joint Terrorist Analysis Center’s conclusion led the British government to reduce its threat assessment level to “substantial” from “severe defined.” British officials told the Times that the reduced threat level did not significantly impact precautions taken against terrorism.]

Photographic records prove that Mohammad Sidique Khan, 30, the man thought to have helped groom the other bombers, arrived in Karachi late last year with the Liverpool Street bomber, Tanweer. The pair were photographed shortly after 2 p.m. on November 19, 2004, as they cleared passport control at Karachi after arriving on a Turkish Airlines flight via Istanbul.

Pakistani investigators are now trying to piece together their movements during the three months before they returned to Britain from Karachi on February 8, 2005.

A third bomber, Hasib Hussain, 18, the youngest of the three ethnic Pakistani Britons, arrived separately in Karachi on July 15, 2004, but returned to Britain via a different route, as yet unknown. Khan and Tanweer were picked up in a car containing “four bearded men,” according to information received by a Karachi evening newspaper, the Daily News.

Police have since visited a hotel in Karachi’s central Saddar area where the two are understood to have stayed for a week before traveling to Lahore by train.

Local sources say the hotel did not keep a database of telephone records that might have assisted police in tracing the pair’s contacts in Karachi.

Once in Lahore, sources say, Tanweer visited several strict Islamic schools, or madrassas, but never registered formally for tuition.

It is thought that a madrassa that has been linked with the banned terror group Jaish-e-Mohammed, the Jamia Manzoorul Islamia, may have been among them. Tanweer then moved on to Faisalabad, where his maternal family originates. It is not known whether Khan accompanied him.

A member of Jaish-e-Mohammed has claimed that he met Tanweer at a madrassa in Faisalabad “a few days” before he was arrested.

Osama Nazir was held late last December in connection with the bombing of a church in Islamabad in 2002. This would therefore place Tanweer in Faisalabad in early December.

This week, Pakistani police detained six people who appeared on telephone records obtained by British police, though the arrests have not provided a breakthrough. “All are cleared now,” a senior official said. “The telephone calls were made only for business purposes and they were not linked in any way to the attacks.”

More significantly, perhaps, intelligence sources say they have arrested five militants, including Qari Usman, allegedly an expert Jaish-e-Mohammad bomb-maker who is suspected have been involved in a plot to kill Pakistan’s president, General Pervez Musharraf, in 2003.

Two of the arrested men are understood to be connected to the madrassa where Osama Nazir says he met Tanweer, the Jamia Fateh-ur-Rahim.

British and Pakistani investigators will want to discover what part Khan and Tanweer’s visit to Pakistan – and their meeting with Mr. Nazir and his associates – played in the attack on London.

However, Pakistan intelligence is also probing a link between Tanweer and a man called Sher Ali, who is described as a recruiting officer for Jaish-e-Mohammad.

The source added that Tanweer was believed to have had contact with Mr. Ali, who is an associate of Mr. Nazir and Amjad Farooqi – another militant, now dead, who was also wanted in connection with the 2003 assassination attempt on General Musharraf.

The fact that Tanweer was accompanied by Khan – who has since been linked to a British suicide bomber in Tel Aviv in 2003 and, by MI5, to a failed Al Qaeda truck bomb plot in London last year – will lead investigators to suspect that the visit was integral to the planning and execution of the London bombings.

The first of Tanweer’s five visits to Pakistan is said to have been in 2001, when the then-18-year-old, accompanied by his father, Mumtaz, enrolled as a volunteer with a pacifist Muslim organization based in Raiwind, south of Lahore, called Tableeghi Jamaat.

Its volunteers are asked to give their time free to proselytize peacefully in the name of Islam.

Sources said that Tanweer worked in Abbottabad in 2001 and then returned in 2002 to volunteer again, for 40 days, this time working in the North West Frontier Province.

It is during this period that Pakistan intelligence sources believe that he might first have come into contact with Sher Ali and taken his first steps toward extremism.

General Musharraf denounced the bombs as “un-Islamic” yesterday and accused groups such as Jaish-e-Mohammed of forcing their ideology on others.

“Launching bomb attacks in London in the name of Islam is not Islam,” he said. He also said some Islamic schools in Pakistan were involved in terrorism and pledged to reform them.