Tensions brewing around a radical mosque in Pakistan's capital burst into street battles Tuesday between security forces and masked militants who have challenged the government by mounting a vigilante anti-vice campaign.

At least nine people were killed and dozens wounded in the clash, which underlined the concern at the spread of Islamic extremism in a country struggling to combat Taliban and Al Qaeda militants.

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Early Wednesday, Pakistan's government warned the armed militants holed up at Lal Masjid, or Red Mosque, to surrender or face punitive action from security forces. It did not set a deadline.

The violence dramatically deepened a six-month standoff at the mosque, whose hard-line clerics have kidnapped alleged prostitutes and police officers in their efforts to impose a Taliban-style version of Islamic law in the capital.

Deputy Interior Minister Zafar Warriach said the dead included four students, three civilians, one soldier and a journalist. Clerics at the mosque claimed 10 of their supporters were killed, according to a lawmaker sent to mediate the dispute.

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Warriach said 148 people were injured, most of them by tear gas fired by security forces.

At nightfall, the city's top security official, Khalid Pervez, said a cease-fire had been reached with the militants. But Warriach emerged early Wednesday to say authorities had run out of patience and demanded the militants lay down their weapons.

"No action will be taken against those who do it, but if anyone displays weapons and comes out, he will be answered with bullets," Warriach said after a meeting of top officials, including Pakistan's president, Gen. Pervez Musharraf.

Warriach did not announce any deadline for the militants to surrender, but warned that "the government has decided that those people from the madrassa who are defaming Pakistan and Islam will face an operation" by police and paramilitary troops.

Officials said the unrest began Tuesday morning when police tried to stop militant students from occupying a government building. Reporters saw dozens of students, including young masked men with guns and black-robed women with long poles, moving toward security forces about 200 yards from the red-walled, white-domed mosque.

Police shot tear gas, and several male students, some of them masked, responded with gunfire. Shooting was also heard from the police position.

Men brandishing assault rifles, pistols and molotov cocktails, some of them wearing gas-masks, then gathered around the mosque, while security forces cordoned off the area with barbed wire and checkpoints and lobbed tear gas canisters at the demonstrators.

At one point, 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.

No such attacks were reported.

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.

Abdul Rashid Ghazi, the mosque's deputy leader, said security forces sparked the unrest 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 the mosque, Ghazi said they "are our guards."

Authorities have been at loggerheads with the mosque for months over a land dispute and its attempts to impose a harsh version of Islamic law in the capital.

Senior officials, including the head of the ruling party, have tried to negotiate a settlement of their grievances. However, clerics have steadily raised the stakes, kidnapping police officers and alleged prostitutes, including several Chinese nationals, and repeatedly threatening suicide attacks if security forces intervened.

Some accuse Pakistan's intelligence agencies of encouraging the crisis to justify a state of emergency and prolong military rule. Musharraf, a U.S. ally who seized power in a 1999 coup, had planned to ask lawmakers for a new five-year term this fall, but that is in doubt because of a public uproar over his attempt to fire the country's top judge.

Musharraf said last week he was ready to raid the mosque, but warned that militants linked to Al Qaeda had slipped inside and the media would blame any bloodbath on the government.

Tuesday's clash set off protests elsewhere in the country.

More than 2,000 students from an Islamic school in the eastern city of Lahore chanted slogans against Musharraf. Mufti Hamidullah Jan, a cleric at the Jamia Ashrafia madrassa, vowed to send his students to Islamabad if the government didn't stop the action against the Red Mosque. "Now is not the time for protests, but jihad," he said.

About 200 supporters of a radical religious party burned tires in the southwestern city of Quetta to protest the police moves against the mosque. "Anyone who is a friend of America, is a traitor," many protesters chanted.