The government kept up its pressure on the Lal Masjid, or Red Mosque, demanding the unconditional surrender of the estimated 400 to 500 people still inside, as many as half of them female students and teachers. Army and police commandos have surrounded the complex and barred access since heavy clashes with armed followers on Tuesday.

Several times during the day and evening helicopters circled overhead, and the security forces exchanged fire with the militants inside the mosque in half-hour bursts of heavy gunfire and explosions. Then, each time the guns fell silent, the troops used loudspeakers to call on those inside to surrender, assuring them safe passage.

Yet government officials conceded that despite some success on Wednesday — when more than 1,100 students surrendered and one leader of the uprising was arrested while trying to escape dressed in a burqa — security forces were now locked in a standoff with the militants, who are intent on imposing Islamic law throughout the country.

More students emerged from the mosque on Thursday, but the interior minister, Aftab Ahmed Khan Sherpao, said there were still up to 60 armed militants inside who were preventing others from leaving.

“There are 50 to 60 hard-core militants with automatic weapons, grenades and petrol bombs, which they have used,” he said at a news briefing here in the capital. “They are the ones who have stopped the women and children from coming out. The majority want to leave.”

“The government is exercising maximum restraint because there are women and children inside, and we don’t want any harm to them,” he added. “The restraint is on the special orders of the president. We have to be patient and wait.”

Six men from inside had been caught jumping over the wall in a bid to escape, he said, adding: “Naturally they cannot sustain it for long. Despondency, panic and confusion would prevail and that would, I am sure, give us the desired result, and they will surrender.”

About 40 people, including some women, escaped from the mosque in the afternoon and were fleeing against the wishes of those in charge inside the compound, Javed Iqbal Cheema, an Interior Ministry spokesman, said late Thursday.

He called on Abdur Rashid Ghazi, the younger of two brothers leading the mosque and its religious schools, to allow all children and students to leave safely.

In telephone interviews with Pakistani television news channels, Mr. Ghazi said he was offering to surrender on the condition he not be prosecuted and be allowed to stay in the compound with his sick mother for a few days.

“We are not criminals,” he told Aaj TV. “They are treating us like criminals. Even with criminals, negotiations take place. It is quite clear that they want killing.”

Government officials were adamant that Mr. Ghazi had to surrender without negotiation. The arrest of Maulana Abdul Aziz, his elder brother, on Wednesday evening has damaged the clerics’ cause, said Tasnim Aslam, a Foreign Ministry spokeswoman.

State television, Pakistan TV, showed a heavily edited interview with the maulana after his arrest in which he was made to don his burqa again and lift the veil for the camera.

Bearded and wearing a white skull cap, the maulana, or teacher, said he had left the mosque to prevent further loss of life.

“I was thinking that if I stay there, then my students will lay down their lives for me, and we were left with no other way,” he said. “I would not use the word ‘escape.’ Shariah” — the Islamic legal code — “allows if a person wants to leave quietly, in hiding, to save one’s life. It was not the question of just my life.”

He made light of the students’ militant activities, saying that no orders had been given to fire on the Pakistani soldiers or to burn down government buildings, and that they had acted on their own. He denied that there were militants inside the compound and said that they had only about 15 Kalashnikovs in the compound, some of which were licensed.

Maulana Aziz denied that women were being used as human shields, but he admitted that the female teachers, among them his wife, who runs the girls’ seminary, were trying to keep the women inside. “The female students were never used as shields,” he said. “We have just given them an inspiration for jihad.”

Two brothers whose 19-year-old sister was in the mosque said they had talked with her by telephone but she was refusing to come out. “She is totally happy, she is not afraid,” said one brother, who identified himself as Abdullah, 34. “I tried my very best to tell her to come out but she wants to be with her teachers.”

The atmosphere inside the mosque seemed a strange mixture of militancy, innocence and religious fervor. Armed men carried automatic rifles and pistols and many wore ammunition vests.

One apparently experienced fighter, tall and heavily built, held a loudspeaker and directed students in the street. “Don’t fall in the trap of the enemy,” he barked. “Guard the mosque and madrasa. Don’t go too far.”

Inside the prayer hall, students sat in groups. Some recited the Koran or offered prayers, seemingly oblivious to the firing of bullets and tear gas. A dozen or so students stood around those who made speeches through the loudspeakers and chanted, “Jihad! Jihad!”

One student shouted into the loudspeaker: “Brothers, don’t fear, victory is near. Our companions across the country have stood up in our support.”