At least 10 people have died in clashes between security forces and militant students at a mosque in the Pakistani capital, Islamabad, officials say.
A soldier, two students and a journalist were among the dead.
After several hours of shooting outside the controversial Lal Masjid (Red Mosque) a ceasefire was negotiated.
Armed students at the mosque and religious schools linked to it have defied the authorities for months in a campaign for Islamic Sharia law.
The mosque and the two madrassas (religious schools) attached to it - one for men, the other for women - have been at the centre of a number of high-profile incidents.
These include the kidnapping of police and people the mosque's leaders say are involved in immoral activities such as prostitution.
Fighting around the Lal Masjid raged throughout much of Tuesday.
More than 140 people were wounded in the violence, officials said.
Speaking to the BBC, Information Minister Muhammad Ali Durrani said the government was still discussing how to handle the situation.
The BBC's Syed Shoaib Hasan who is outside the mosque says the ceasefire was negotiated by a politician from the MMA, a coalition of Islamic parties.
Later on Tuesday, students also attacked the nearby Ministry of Environment, setting fire to a number of vehicles in its car park.
At the height of the violence, regular police and paramilitary units ringing the mosque compound were replaced by what appeared to be special forces, our correspondent says.
Ambulances and journalists were told to move further away from the scene.
People fled from busy shopping areas as masked students traded fire with security forces. Dozens of other students - mostly armed with sticks and petrol bombs - patrolled the area.
Among those killed was at least one passer-by, officials said. The journalist who died was a cameraman filming for a private television station.
The killing of the paramilitary soldier was the first fatality in the prolonged stand-off between the authorities and the students.
A senior paramilitary official said the soldier had been "killed in the firing from inside the mosque".
Doctors at a nearby hospital said they were treating about 60 people suffering the effects of tear gas, the Associated Press news agency reported.
Several students had bullet wounds, doctors said.
Critics have attacked the government for failing to enforce its authority in the capital.
President Musharraf has previously said security forces cannot raid the mosque for fear of reprisal suicide attacks.
BBC correspondents say it is thought the mosque has powerful friends in the security services, which has prevented the authorities from taking action.
But the fact that people have now been killed in the stand-off suggests the situation may be turning against the mosque leaders, our correspondents say.