The powerful explosion happened just after thousands of Islamist hardliners had called for the public hanging of President Pervez Musharraf over last year's bloody raid on the mosque, in which 100 people died.

Dozens of dead and injured policemen lay on the ground in pools of blood after the blast, their blue uniforms ripped to shreds by the force of the explosion.

'A young man walked into the police contingent and apparently blew himself up. We have 11 policemen dead,' a senior Pakistani security official said.

Twenty-five others were wounded, most of them also police.

'The blast happened 15 minutes after the meeting dispersed. A heavy contingent of police was at a main crossing several hundred metres from the mosque and they were targeted in the attack.'

Interior Ministry chief Rehman Malik said: 'The whole event at the mosque went smoothly but then the suicide bomber targeted the security.'

Television footage showed bearded students frantically running towards the scene and ambulances bringing the wounded to hospitals.

Prime Minister Yousuf Raza Gilani condemned the blast and ordered an inquiry, state media said.

The storming of the mosque on July 10 last year, following a week-long siege, sparked a wave of suicide attacks across the country blamed on Al-Qaeda and Taleban militants.

In fiery speeches, Islamists condemned the military operation against the mosque, blaming Mr Musharraf for the carnage which they claimed was carried out at the request of the United States.

'Musharraf, then Interior Minister Aftab Sherpao, and others who were responsible for the bloodbath should be tried and hanged publicly,' Islamist leader Idrees Haqqani said yesterday.

The speakers also called for jihad or holy war against so-called infidel forces, including American and Nato troops fighting militants in Afghanistan.

Speakers also threatened unspecified action if the mosque's jailed leader Abdul Aziz - who was caught fleeing in a woman's burqa on the second day of the siege - was not released.

The rally speakers also announced that they would move to re-open a seminary for women destroyed in last year's operation, and demanded the government hand back control of the complex to its former administration.

The female students from the seminary became a symbol of the hardline mosque's defiance last year, and it was their kidnapping of several Chinese women suspected of being prostitutes that sparked the deadly siege.

AGENCE FRANCE-PRESSE