Security forces clashed with militants outside a radical mosque in the Pakistani capital Tuesday, triggering gunfire that killed two police officers and one soldier, officials said.
The students later pelted two government buildings, including the Ministry of Environment, with rocks and set them ablaze, and torched a dozen cars in the ministry's lot.
About four hours after the first shots were fired, the government sent a lawmaker into the mosque to try to negotiate an end to the clashes, according to local media reports.
The battle marked a major escalation in a standoff at the Lal Masjid, or Red Mosque, whose clerics have challenged the military-led government by mounting a vigilante anti-vice campaign in Islamabad.
Trouble began when student followers of the mosque, including young men with guns and dozens of women wearing black burqas, rushed toward a nearby police checkpoint early Tuesday afternoon.
Police and paramilitary Rangers fired tear gas and, as the students retreated, an Associated Press photographer saw at least four male students, some of them masked, fire shots toward security forces about 200 meters (yards) away.
Gunfire was also heard from the police position.
A man used the mosque's loudspeakers to order suicide bombers to get into position.
"They have attacked our mosque, the time for sacrifice has come," the man said.
Hours later, dozens of students were patrolling the area around the mosque, and sporadic shots were still heard.
Security forces, some riding in armored vehicles, cordoned off the area with barbed wire and checkpoints and continued to fire tear gas at the demonstrators from a distance. Shops in the area, about four kilometers (2.5 miles) from the government district, were shuttered.
Deputy Interior Minister Zafar Warriach said officials were in touch with the mosque administration to try to defuse the situation.
"Despite provocation from the Lal Masjid, we are not using force," Warraich said on state-run Pakistan Television.
However, Warriach said it was the duty of the government to protect the life and property of its citizens, and "we will do it."
Some of the students carried gas masks and several were seen with gasoline-filled bottles and Molotov cocktails. About a dozen were armed with guns, including AK-47 assault rifles.
Abdul Rashid Ghazi, the mosque's deputy leader, said the Rangers sparked the trouble by erecting barricades near the mosque.
"The government is to be blamed for it," he said.
When asked about the presence of armed students at his mosque, Ghazi said they "are our guards."
One paramilitary soldier hit in the clash died at a hospital, Interior Minister Aftab Khan Sherpao said. The two police died of bullet wounds at another clinic later, a ministry official and a doctor said. Both asked for anonymity because they were not authorized to talk to the media.
Doctors at various hospitals said they had admitted about 100 people. Most were suffering from the effects of tear gas, but they also included several students - both male and female - with bullet wounds, the medics said.
Witnesses said a newspaper reporter and a cameraman were caught in the crossfire and taken to a hospital with bullet wounds.
Authorities have been at loggerheads with the mosque for months over a land dispute and after its followers began a campaign to impose a Taliban-style version of Islamic law in the capital.
Students have carried out a string of kidnappings of police officers and alleged prostitutes, including several Chinese nationals, and have threatened suicide attacks if security forces intervene.
Hundreds of police and paramilitary Rangers have taken up position near the mosque in recent days in what officials have said is an effort to contain their activities.
President Gen. Pervez Musharraf said last week that he was ready to raid the mosque, but warned that suicide bombers from a militant group linked to al-Qaida had slipped into the mosque and that the media would blame any bloodbath on the government.