Military ruler Musharraf said that the hardline students holed up inside the Red Mosque for the past five days must immediately free women and children allegedly being held as human shields, or face death.

"They should not prolong. They should surrender and hand over their weapons, otherwise they risk being killed," Musharraf told reporters in his first public comment on the confrontation.

"Our concern is for children and women and we are showing a lot of patience and restraint."

Fighting intensified at the now bullet-pocked mosque on Saturday. Fierce clashes erupted at lunchtime while troops blew up the complex's petrol tank during the night, sending flames high into the air.

The firebrand cleric leading the resistance, Abdul Rashid Ghazi, said Pakistani forces had killed 30 female and 40 male students in the siege. The women were buried at the site, he said.

The government says the toll is 19, including a soldier and several civilians.

The mullah said he and his followers had enough rations, arms and ammunition inside the compound to "fight for another 25 to 30 days and we will do that, God willing."

Ghazi also signalled his defiance by saying that he was telephoned by a man who claimed to have shot at Musharraf's aircraft on Friday in revenge for the siege.

"I received a telephone call yesterday from a man I did not know," who offered his "congratulations" before news of the attack on the president became public, Ghazi told AFP by telephone from the mosque.

"He said, 'I fired at Musharraf's plane just a while ago.' He said that Musharraf survived," said Ghazi, the deputy leader of the mosque.

Security officials said earlier they were probing possible links between the mosque operation and the failed bid to shoot down the president's plane as it took off from a military airbase at Rawalpindi, near Islamabad.

Musharraf has survived at least three other militant attempts to kill him.