New York: Hopeful of gleaning vital intelligence from the captured al-Qaida operative Khalid Sheikh Mohammad, American and Pakistani officials believe that his arrest has dealt a "severe blow" to operational capability of Osama bin Laden's terror network.

Sheikh Mohammad, who was arrested in Pakistani city of Rawalpindi on March 1, may hold the greatest intelligence treasure, 'Time' magazine reported quoting the officials.

"If I had to choose who is bigger catch, Osama bin Laden or Khalid Shaikh, I'd say Khalid Shaikh," a Pakistani intelligence official said.

A senior Bush Administration official said the US is now closer to finding bin Laden after Sheikh Mohammad's capture than it was before.

Rohan Gunaratna, author of a study of al-Qaida, said Sheikh Mohammad's arrest would "cut al-Qaida's operational ability by 50 per cent at least in the next one to two years".

Last week's classified Federal Bureau of Investigation (FBI) intelligence bulletin said the arrest "deals a severe blow to al-Qaida's ability to plan and carry out attacks against the United States".

Sheikh Mohammad, speaking to his interrogators last week, referred to himself as the 'Brain', Time said quoting a US intelligence source.

He was interrogated first by Pakistani authorities who were anxious, said a source, that he might have been planning an assassination attempt on President Pervez Musharraf.

Sheikh Mohammad's name came up so often in the communication intercepts that triggered last month's orange alert that he seemed capable of simultaneously orchestrating several different plots in the US and elsewhere, a senior US counter- terrorism official told 'Time'.

Law-enforcement authorities in the United States are especially concerned that al- Qaida may be planning attacks on national monuments in the US and trying to disrupt the economy, the magazine said.

New York authorities and the FBI have been paying particular attention to securing the bridges into Manhattan, especially the Brooklyn Bridge, which is an icon and a vital economic artery.

After being interrogated by Pakistani officials, Sheikh Mohammad was flown in a US Chinook helicopter to the American air base at Bagram, Afghanistan, North of Kabul, according to Pakistani sources.

US sources would not confirm that Sheikh Mohammad was taken to Bagram, but an Afghan general told the magazine that he saw Mohammad taken off the helicopter, hooded and manacled. He may or may not still be there.

A Jordanian official told 'Time' that at the end of last week, Sheikh Mohammad was being held and questioned in Amman, Jordan. US sources would not comment on the claim.

PTI