A senior soldier has been killed in the latest clashes with Islamist students barricaded inside a mosque in Pakistan's capital, Islamabad.

The army said the commando officer had been overseeing an operation to blast holes in the walls of the Red Mosque.

Troops were carrying out the attack in an attempt to allow women and children trapped inside the mosque to escape.

The militants responded with heavy fire. About 20 people have been killed since the standoff began last Tuesday.

Another soldier was wounded in the clashes. Both men belonged to the army's Special Services Group.

President Pervez Musharraf told the students they have no option but to surrender.

"If they don't surrender, they will be killed. We've shown great patience because we don't want people to be killed" he said.

He spoke on Saturday after troops outside the mosque stopped a delegation of Islamic figures from entering to negotiate with those in the complex.

The delegates wanted to convince the mosque's leader, Abdul Rashid Ghazi, to allow women and children to leave.

Water and power to the mosque have been cut off and food is said to be getting scarce.

The BBC's Syed Shoiab Hasan, in Islamabad, says he has heard intermittent gunfire in the area and the boom of heavy weapons.

An increased military presence on the streets, combined with the refusal to let the political delegation through to the mosque, suggests that the government is now closing the door to negotiation, our correspondent adds.

On Saturday police also seized control of a madrassa, or religious school, several kilometres away, which is also run by clerics from the mosque.

They described the Jamia Faridia as a "powerhouse" for the mosque and said several of its students were involved in the stand-off.

Abdul Rashid Ghazi has said he and his followers are willing to lay down their guns but would rather die than surrender.

He told the BBC on Saturday that as many as 1,800 followers remain in the mosque, and claimed to have buried 30 female students in a mass grave in the compound.

More than 1,000 supporters left earlier this week under mounting pressure from security forces.

About 60 of those remaining are said to be hardliners.

They have led a morality campaign which included the abduction of police officers and people accused of running brothels, as well as raids on music and DVD shops.

PHOTO CAPTION

A soldier of Pakistan army monitors behind a bunker at vicinity of Lal or Red Mosque in Islamabad, Pakistan on Sunday, July 8, 2007. (AP)

BBC