US names 'mastermind' of twin tower attacks

American officials said yesterday they had identified a new candidate as the possible mastermind of the 11 September attacks.

He was identified as Khalid Sheikh Mohammed, a Kuwaiti-born member of Osama bin Laden's al-Qa'ida organisation who is a blood relative of Ramzi Yousef, who was involved in the first attempt to blow up the World Trade Centre in 1993.

The officials said they believed Mr Mohammed was at large somewhere in the border region between Afghanistan and Pakistan. He had previously been implicated in the thwarted attempt by Yousef and others to blow up 12 airliners above the Pacific Ocean in 1995 and there were suspicions he was involved in the bombings of the US embassies in Kenya and Tanzania in 1998.

It was, however, never previously known for sure that Mr Mohammed was involved with al-Qa'ida, let alone at such a high level. New information, suggesting he was deeply involved in the operational and financial planning of the 11 September attacks, came largely from captured al- Qa'ida members, including Abu Zubeida, one of Osama bin Laden's lieutenants who has been talking to US authorities since being captured in Pakistan in March.

It is now believed Mr Mohammed had more to do with 11 September than Mr bin Laden. "It looks like he's the man, quite honestly," a Bush administration official told the Los Angeles Times.

"We believe he is probably the leader of this. We have reason to believe it was his idea to create the plan for the four hijackings and discussed the plan with ... bin Laden." If the officials are right – and they say they have cross-checked their information since first hearing about Mr Mohammed's role from the captured fighters – then they will have discovered the first truly compelling link between al-Qa'ida and Ramzi Yousef, who is in a maximum-security prison in America.

There was always a tremendous amount of circumstantial evidence to suggest the two attacks on the World Trade Centre were conceived by the same group of people but no concrete link.

Yousef has never talked, and there has been much speculation about his true identity – whether he is a Kuwaiti-born Pakistani, as Mr Mohammed appears to be, or whether he stole the identity of a Kuwaiti-born Pakistani during the Iraqi occupation of Kuwait in 1990-91 and is, in fact, somebody completely different.

Some hawks in the Bush administration, anxious to launch a military invasion of Iraq, believe Yousef is an Iraqi agent and that the man ultimately responsible for many of the terror plots of the past decade is Saddam Hussein.

The decision to go public with their information might have been prompted by the criticisms levelled at the Bush administration and intelligence services over their failure to prevent the 11 September attacks and the slow progress made in the investigation.

Mr Mohammed, who is believed to be 36 or 37, has been on the US list of most wanted terrorists since Decemberalthough he was initially mentioned only in connection with the 1995 airliner plot. The officials did not specify what his relationship was to Yousef, who is serving a life sentence in the federal "super-maximum security" prison in Florence, Colorado, for his part in the earlier terror attacks.

* In a move that has angered Arab and immigration groups, the US government will order up to 100,000 visitors a year – most of them Middle Eastern men – to be fingerprinted and photographed on entry.