Terror mastermind 'was preparing more attacks' on US

The alleged al-Qa'ida mastermind Khalid Sheikh Mohammed was plotting attacks against commercial targets in the United States and the Arabian peninsula, the plans for which may already have been set in motion, American intelligence officials said yesterday.

His arrest in Pakistan at the weekend and subsequent interrogation should provide a "treasure trove" of information about the terrorism network, they said.

A Bush administration official said the man accused of being the main operational planner behind the 11 September attacks was placed in their custody yesterday by Pakistan and had already been taken out of the country to an undisclosed location. The experience of other suspects suggests he may have been transferred to a US base in Afghanistan or to Guantanamo Bay in Cuba.

Officials said the 37-year-old would be subjected to "extreme pressure" to force him to talk but said this stopped short of torture. Interrogators believe that the next 48 hours will be crucial. Officials said they thought he would be subjected to round-the-clock interrogations, psychological manipulation, exposure to bitter cold or intense heat, and even "truth drugs".

Tom Ridge, the US Homeland Security Secretary, said the al-Qa'ida suspect was believed to have been plotting further attacks, which is partly why the warning level in the United States was raised recently. "Some of the concerns we had that caused us to raise the threat level were attributable to the planning he was involved in," he said.

Officials said they had already obtained a wealth of information about al-Qa'ida from the house in Rawalpindi where Mohammed was seized early on Saturday. Experts from the CIA and other intelligence agencies have examined computers, computer disks, mobile phones and documents they hope will provide names, locations and potential terrorist plots of al-Qa'ida cells in the United States and around the world. Mohammed is also believed to have details about the group's finances.

"It could be the mother lode of information that leads to the inner workings of al-Qa'ida," an official told the Los Angeles Times. "How they work, where they work, who they are, what their financial structure is."

Another US official claimed the authorities had identified "several [targets] in the United States and elsewhere", adding "There were indications that he was involved in planning attacks [that were] not far away."

A report on Newsweek magazine's website claims the Kuwaiti-born suspect was overseeing possible planned attacks by al-Qa'ida sleeper cells on US suspension bridges, petrol stations and power plants in big cities. The magazine said that this information came from at least one al-Qa'ida prisoner who knew Mohammed.

"He indicated that Mohammed would go back to plots that he had previously worked on that had not yet come to fruition, and there was other information from other sources which pointed to the same kind of things that we were hearing from the detainees," an official told the magazine.

The National Security Agency is said to be eavesdropping even more closelyon electronic sources for an expected flurry of e-mails and phone calls within al-Qa'ida.