A Pakistani cleric holed up in a besieged mosque in the capital declared yesterday he would rather die than surrender, dramatically upping the stakes amid claims human shields are being held inside.

Gunmen meanwhile fired on President Pervez Musharraf's plane with a Taliban-style antiaircraft gun in an attack that officials said had possible links to the mosque stand-off. Musharraf was unharmed in the incident.

Abdul Rashid Ghazi, deputy leaderof the pro-Taliban Lal Masjid, or Red Mosque, vowed not to give himself up to government forces on the fourth day of the bloody confrontation there that has already

claimed 19 lives.

The government rejected a conditional surrender offer last night by Ghazi, whose brother Abdul Aziz was captured on Wednesday while trying to flee the mosque dressed in a burqa.

"We have decided that we can be martyred but we will not surrender. We are ready for our heads to be cut off but we will not bow to them," he told the private Geo television station.

"This may be my last conversation with you."

Heavy gunfire and explosions rocked the mosque early on Friday and there was no call for pre-dawn prayers from the mosque's loudspeakers, indicating the damage inflicted by security forces on the fortified complex.

Troops backed by armoured personnel carriers and helicopter gunships have been moving closer to the mosque and have blown up much of its surrounding walls.

A mosque official said, on condition of anonymity, that there were casualties in the early Friday gunbattles and the building had been hit by further mortar fire from securityforces.

During a lunchtime relaxation of the shoot-on-sight curfew in force around the complex, militants shot and wounded a man coming to see his daughter inside an Islamic school attached to the mosque, officials said.

Residents living near the mosque said the siege was taking its toll.

"The last few days have

changed my son's mind. He is 10 years old and started talking about bullets and shells," said housewife Nasreen Jehan.

Hundreds of Islamic students are still inside the mosque compound, along with up to 60 "hardcore" armed militants, officials have said.

Musharraf had earlier ordered that no military action should be taken until women and children were out of the mosque, but repeated that only an unconditional surrender was acceptable, officials said.

"The president has ordered authorities that force should not be used until we are sure that all the innocent people, who are being used as human shields, have come out," deputy information minister Tariq Azeem told AFP.

The militants inside are believed to be armed with assault rifles, grenades and petrol bombs, Interior Minister Aftab Sherpao said late Thursday.

Ghazi and Aziz have both denied that anyone was being kept against their will.

Aziz urged his followers to give themselves up on Thursday in a bizarre interview with state television conducted while wearing the burqa in which he was captured.

He has been remanded in custody by a court, charged with plotting terrorist attacks and kidnapping people, including seven Chinese nationals abducted by his students from an acupuncture clinic for allegedly running a brothel.

Musharraf, a key US ally who is facing a political crisis ahead of elections later this year after ousting the country's chief justice, has received a popularity boost at home since finally cracking down on the mosque.

The clerics led a vigilante morality campaign in Islamabad which has included the abduction of police officers and people accused of running brothels as well as raids on music and DVD shops.

But in a sign that Islamic extremists are still targeting him following four assassination attempts, shots were fired after Musharraf's aircraft flew from a military base to visit flood-hit southern Pakistan.

"It was an unsuccessful attempt to shoot the president's plane," one official told AFP.

He said the plane was not within range of the improvised anti-aircraft gun found at a house in Rawalpindi, near Islamabad.

One suspect was arrested, he added.