ISLAMABAD, Pakistan (CNN) -- Police seized munitions on Friday at a house near Islamabad's airport after receiving reports of rooftop gunfire around the same time President Pervez Musharraf's plane was taking off, authorities told CNN.
Security officials examine a long barrelled anti-aircraft gun after gunmen fired at President Musharraf's plane.
Police raided a vacant house in Rawalpindi, near the Islamabad airport, where they seized two machine guns situated on the rooftop and other weapons in the house.
Intelligence sources said they received reports that the guns were being set up and fire was heard. This was around the same time the president's plane was taking off.
Sources earlier described the weapons as anti-aircraft guns, but they are now being described as 7.62 mm improvised machine guns -- the kind used by Taliban militants in Afghanistan.
The people who heard the fire called police, who rushed to the house, set up a cordon, and began a search.
The distance between the house and the runway is around 6.5 to 7 kilometers, and the weapons are said to lack the power and the accuracy to effectively strike a target from such a distance.
The army denied a link between an attempt on Musharraf and the weaponry, but police are pursuing the reports.
Pakistani forces and radical Islamic students in Islamabad -- Pakistan's capital -- remained locked in a tense standoff at the Lal Masjid, or Red Mosque, punctuated by heavy explosions and periodic exchanges of gunfire, a four day siege that has resulted in at least 24 deaths.
The violence began Tuesday when about 150 militant students attacked a police checkpoint close to the mosque. Police fired tear gas and the students fought back with sticks and guns and took refuge in the mosque.
In the latest developments on Friday, a rocket was fired at an armored police vehicle from inside the mosque, and a group of parents were fired upon when they tried to enter the mosque to retrieve their children. A father was injured in that incident.
The Pakistani government has refused to meet a demand by those inside the controversial mosque that they be allowed to surrender without facing arrest.
Intelligence sources said the 850 to 900 people who remain holed up inside are facing a food and water shortage that is making living conditions inside miserable. Pakistani authorities say, while about 100 of them are well-armed hard-liners, there are women and children among them.
Maulana Abdul Aziz, the top cleric of the Red Mosque, also called on the students to surrender, a day after he was arrested trying to slip out of the mosque disguised in a burqa -- the head-to-toe covering worn by some Muslim women.
An estimated 1,200 of the students have already surrendered, with around seven giving up on Friday.
Pakistani forces have demolished the Red Mosque's front walls and warned students by loudspeaker they had one last chance to surrender before a full attack took place, intelligence and military sources told CNN on Thursday.
Tensions have been simmering between police and the students at the mosque, who are blamed for a string of recent kidnappings of civilians, Chinese nationals and Pakistani police. The government has been investigating the activities of the mosque, whose students who are demanding sharia, or Islamic law, be instituted in Islamabad.
As part of the clampdown on the mosque compound -- which includes several madrassas, or religious schools -- police set up a security perimeter around the area last week. E-mail to a friend