Senior bin Laden aide captured by Northern Alliance

One of Osama bin Laden's top lieutenants, a son of the so-called "blind sheikh" Omar Abdel-Rahman, has been captured by the Northern Alliance and is being held in Mazar-i-Sharif, US officials said yesterday.

Ahmed Abdel-Rahman appears to have been seized in northern Afghanistan about a month ago, and is by far the most senior figure in Mr bin Laden's al-Qa'ida network to have been taken alive. He could now become a test case for the United States as it plans to try top al-Qa'ida operatives by secret military tribunal.

Believed to be an important recruiter for al-Qa'ida and a member of Mr bin Laden's inner circle of advisers, Mr Abdel-Rahman's role was above all symbolic: he bore the legacy of his father, a much revered figure in Islamist circles who has been in prison in the United States since 1995 for helping to plan a series of attempted attacks on bridges and tunnels in New York.

For several years, Omar Abdel-Rahman preached an extreme version of jihadagainst the US from his base in New Jersey, and is believed to have inspired the organisers of the 1993 truck bombing of the World Trade Centre. At his sentencing in 1996, the Egyptian-born cleric described the US as an "infidel country" whose civilisation would be destroyed.

Ahmed is the son who was most active in the movement, spending several years in Afghanistan alongside Mr bin Laden. Little is known of the circumstances of his capture or his treatment since. Unconfirmed reports of his arrest first surfaced a month ago, with reports that his brother Mohammed was also being sought in Afghanistan. A third brother, Abdullah, told reporters in Cairo that he had received the news of Ahmed's capture in late October but had been unable to find out anything else since.

The Pentagon said yesterday that it had "no evidence" of his capture. Other US officials confirmed Mr Abdel-Rahman was in custody.

Montasser el-Zayat, a prominent defence lawyer for Islamic militants in Egypt, said the younger Abdel-Rahman had been interrogated by US officials as well as the Northern Alliance. There was also evidence, he said, that the captive had been tortured.

Bush administration officials appear to be relishing the prospect of using Mr Abdel-Rahman, and a dozen other arrested al-Qa'ida operatives, as prototypes for the system of secret military tribunals authorised by the President earlier this month.

The system has come under heavy criticism from human rights groups and some members of Congress, who say it violates constitutional guarantees of a fair trial and compromises efforts by US diplomats to stop other countries from trying its enemies in this way.

The criticism appears to be having some effect, with the Justice Department saying it is considering checks and balances to make the system fairer. Originally, the President's executive order suggested defendants could be swiftly tried and executed on the authorisation of just two-thirds of the military commission which would act as judge and jury.