A Briton of Indian descent, alleged to be the mastermind behind the July 7 London [Images] bombings that killed 56 people, has reportedly been arrested in Zambia as police on Friday in London interrogated one of the men suspected of attempting to launch a similar attack two weeks later and stepped up hunt for those on the run.

Haroon Rashid Aswat, who is of Indian descent and grew up in West Yorkshire, was arrested last week and is being held in Lusaka, where both British and United States ani-terrorism investigators have travelled, The Times reported.

British officials would not immediately elaborate on the report, but a Foreign Office spokeswoman said, "We are seeking consular access to a British national who is reported to be in custody in Zambia."

Aswat, claimed to be a senior British Al Qaeda [Images] operative, whose association with the terror network dates back to 10 years, is believed to have flown out from Heathrow airport hours before the four suicide bombers killed 52 rush-hour commuters and themselves on three tube trains and a bus on July 7.

Investigators have sought him since discovering that he made up to 20 calls from his mobile to two of the bombers.

Quoting intelligence sources, The Times reported that prior to the deadly bombings Aswat visited the hometowns of all four bombers as well as selected targets in London.

• The London Blasts

Aswat is also being sought by the Federal Bureau of Investigation over accusations that he tried to set up Al Qaeda training camps in the US.

FBI documents obtained by the paper reveal details of how a London-based cleric sent Aswat to America in 1999 to set up camps in Oregon for US-born recruits.

The documents indicate that Aswat spent three months in US and engaged in firearms and poisons training, but decided against using a remote ranch in Bly as an Al Qaeda camp.

The Central Intelligence Agency is keeping in close touch with his interrogation and British detectives are seeking permission to speak to him.

The FBI is to question a number of figures held in the US, including James Ujaama, an American converted to Islam who met Aswat, and a second Al Qaeda emissary in Seattle.

Ujaama has pleaded guilty to assisting the Taliban and is now 'cooperating witness' who has given details of Aswat's activities in the US.

Aswat flew into New York on November 26, 1999, on an Air India flight with Oussama Abdullah Kassir, who has Swedish nationality, the paper said. Kassir, 38, described himself as a 'hitman for Osama bin Laden' and claimed to have fought in Kashmir and Afghanistan.

Ujaama drove the pair to the ranch, but they complained that it did not have the facilities -- especially barracks for potential recruits -- that they had been led to believe existed, the daily reported.

The police were, meanwhile, interrogating Somali-born Yasin Hassan Omar, 24, who was arrested in Birmingham two days ago, at London's high-security Paddington Green police station.

They have 14 days to question Omar, one of the four suspected bombers, who, exactly two weeks after the July 7 blasts, tried to launch a repeat attack on London's transport system.

Omar is suspected of trying to blow up an Underground train near central London's Warren Street train station. The other three suspected bombers were still on run.

"We are in a sombre moment and it does remain possible that those at large will strike again," London police chief Ian Blair cautioned on Thursday.