A suicide bomber struck at the heart of Pakistan's military establishment today, killing at least seven people at a checkpoint less than half a mile from the residence of President Musharraf.

The bomber blew himself up after being stopped by policemen guarding the road to army headquarters in the city of Rawalpindi. Three policemen and at least four passers-by were killed in the blast, as well as the bomber himself.

It was not clear if Pakistan's military ruler was the target of the attack. General Musharraf has already survived at least three assassination attempts - two in December 2003, and one in July as his plane took off from Rawalpindi’s airport.

Officials said that General Musharraf was hosting a top-level meeting in an office more than a mile from the bombing.

Suicide and roadside bomb attacks on security forces have multiplied since commandos stormed the Red Mosque in the capital, Islamabad, in July to crush a Taleban-style movement. More than 100 people were killed in the fighting.

The attack happened in a zone of the army's main garrison which is home to the country's top generals, close to the residence of Tariq Majeed, chairman of the joint chiefs of staff, and left the road strewn with human flesh and torn clothing.

"When police officers asked him to halt, the attacker got panicked. And as the police tried to capture him, he blew himself up," said Saud Aziz, the Rawalpindi police chief. "Our officers died to protect the citizens of Pakistan."

Among the dead was an elderly man who had been riding by on a bicycle. Police said women and children aboard a passing minibus were also killed and injured.

Investigators cordoned off the area to retrieve evidence. A policeman climbed an overhanging tree to dislodge part of the bomber’s severed head, reporters said.

While there was no immediate claim of responsibility, Pakistan has been rocked by a string of suicide bombings mostly blamed on Islamic extremists.

An attack on the homecoming parade of the former premier Benazir Bhutto on October 18 in the southern city of Karachi killed more than 140 people. In Rawalpindi, south of Islamabad, two blasts in September killed 25 people and wounded more than 60, many of them on a Defence Ministry bus.

Those attacks were part of a huge surge prompted by General Musharraf's decision in July to crack down on militants tightening their grip on areas along the Afghan frontier, which has become a haven for Taleban and al-Qaeda militants.

Last week, Pakistan sent troops to tackle supporters of a pro-Taliban cleric in the northwestern district of Swat. Officials say four days of violence in the once-peaceful mountain region left around 100 people dead.

General Musharraf is wildely expected to join forces with Ms Bhutto if her party fares well parliamentary elections scheduled for January in a 'moderate' alliance that makes both a prime target for extremists.

Extremists are trying hard to secure a "big catch," said Sheikh Rashid, a senior Cabinet minister and close political ally of the President. "There may be some forces who want to give some big message that they are here, they are in Rawalpindi, they are in Islamabad," Mr Rashid told Dawn News television. "This is a very critical time and critical situation."

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