Pakistan on Monday denied handing over Khalid Shaikh Mohammed, mastermind behind the September 11 attacks, to US custody saying the top Al Qaeda operative was being interrogated by the country's law enforcing agencies.

Khalid Shaikh is still in police custody in Pakistan along with his Arab and Pakistani accomplices, who are yet to be identified, foreign office spokesman Aziz Ahmad Khan told reporters in Islamabad.

They were arrested on Saturday, in a raid witnesses said was conducted by fair-skinned English-speaking persons, reportedly Americans, along with Pakistani officials, from the Rawalpindi residence of a Jamaat-e-Islami leader.

Khan, however, insisted Shaikh was arrested by the ISI and the country's other security agencies adding that the identity of all three persons is yet to be well established.

Interior Minister Faisal Saleh Hayat also said no foreign agency was involved in the raid. "We carried out this operation for our own security concern. We shall continue to conduct such operations until terrorism is rooted out in Pakistan," he was quoted by the official APP news agency as saying.

Shaikh is believed to be number three in the Al Qaeda after Osama bin Laden and Ayman al Zawahiri.

His arrest was widely criticised at mammoth demonstrations held against a possible US-led war against Iraq.

At a rally organised on Sunday by the Islamist alliance Muttahida Majlis-e-Amal in Karachi, the fundamentalist parties attacked the government for cooperating with the US in the crackdown against the Al Qaeda and the Taliban.

The MMA leaders told the protestors that an attack on Iraq would be considered as an attack on the Muslim world and warned that the people would remove the present  government if it did not oppose the second US resolution in the United Nations Security Council.

They asked the Organisation of Islamic Conference countries to prevent American from waging war against Iraq.

Shaikh is understood to be a big catch in the US hunt for Osama bin Laden and other Al Qaeda and Taliban fugitives. He is believed to be behind the Sept 11, 2001, terror strikes on the World Trade Center and the Pentagon that killed over three thousand people. However, he has not been charged in the Sept 11 attacks.

He was indicted in 1996 by a US court in connection with conspiracies in the Philippines to bomb trans-Pacific airliners and crash a plane into the CIA headquarters.

He is alleged to be behind April's bombing of a synagogue in Tunisia that killed at least 19 tourists.

His nephew Ramzi Yousef was convicted of exploding a bomb in the World Trade Centre, New York in 1993 . One of his brothers is an Al Qaeda activist while another died in Pakistan when a bomb he was making exploded.

PTI