London: Two of Osama Bin Laden's closest aides holed up in Pakistan have revealed for the first time how they masterminded the September 11 attacks on America, boasting they want "a thousand operations like these".

The two ring leaders, Khalid Sheikh Mohammed, 38, and Ramzi Binalshibh, 30, are among the Federal Bureau of Investigation's (FBI) most wanted terrorists. They have evaded capture despite 25-million Pound bounties on their heads.

Speaking at a hideout in Pakistan, they gave a chilling account of how they organised and executed the death flights with bin Laden's approval. One of their agents also claimed that bin Laden was "alive and well", although he provided no evidence.

Khalid, the head of al-Qaida's military committee, devised the idea of targeting "prominent" buildings in America. Binalshibh co-ordinated the operation from his base in Germany, where he shared an apartment in Hamburg with Mohammed Atta, the lead hijacker.

In an exclusive interview published in 'The Sunday Times' on September 8, they spoke of their pride in the devastation and slaughter inflicted on what they refer to as "Holy Tuesday".

"The attacks were designed to cause as many deaths as possible and to be a big slap for America on American soil," Khalid said.

The interview with the two terrorists was conducted in June by Yosri Fouda, the chief investigative reporter for the al-Jazeera TV channel. It will be shown on September 12 night.

He was invited by a go-between to Karachi, where, after a series of complex journeys with several handlers, he was blindfolded and driven to a six-room apartment where Khalid and Binalshibh were hiding out.

PTI