Islamabad: The Pakistan government has set a deadline of 11 a.m. on Wednesday for militant students at a mosque in the capital to surrender after 11 people were killed in clashes a day earlier, a spokesman said.

Overnight, commandos and army soldiers joined paramilitary troops and police sealing off Lal Masjid, or Red Mosque, in the heart of Islamabad, but there has been no assault, and gunfire had died down.

"The government has set an 11 a.m. deadline for students to surrender," Secretary of Information Anwar Mehmood told reporters. "I can't say what will be the next step."

Pakistani troops had sealed off the area around a mosque in the capital and imposed a 24-hour curfew on Wednesday.

Violence erupted on Tuesday after a months-long stand-off with a Taliban-style movement headquartered at Lal Masjid, or Red Mosque, less than a couple of kilometres from parliament and a protected enclave for foreign embassies.

Soldiers moved 12 armoured personnel carriers, mounted with machineguns, into the area as gunfire subsided overnight.

Deputy Interior Minister Zafar Warraich told a news conference that no action would be taken against students who lay down their weapons and surrender, but anyone who tried to fight would be shot.

"A bullet will be responded with by a bullet," he said.

Power was cut off in the neighbourhood, barbed wire at the ends of roads, and journalists were expelled from the area.

"The army is turning back anyone who tries to leave their street, and there is no traffic on the roads," said Reuters correspondent Matiullah Jan, a resident in the curfew zone.

The Interior Ministry said nine people had been killed, but Islamabad hospital officials later said the toll was 11. About 150 people were taken to hospital, 30 with bullet wounds, others suffering from the effects of tear gas.

A soldier and at least four students were among the dead, as well as a television cameraman and people caught in crossfire.

Liberal politicians have pressed President Pervez Musharraf to crack down on Lal Masjid's clerics and their followers, who have threatened suicide attacks if force was used against them.

The religious hardliners have confronted authorities for months, running a vigilante anti-vice campaign and campaigning for observance of strict Islamic law.

Authorities had not used force for fear it could provoke attacks or lead to casualties among female students at a religious school, or madrasa, in the mosque compound.

Clerics acting as intermediaries had held talks with leaders of the student movement and the government overnight, but there was no sign of a break in the deadlock.