Shi'ite Muslims in Pakistan have taken to the streets to protest the death of one of their religious leaders. As the government extends its curfew at the site of recent sectarian unrest, some foreigners have reportedly been evacuated from the troubled region in the north of the country.

Shi'ite activists took to the streets in major cities across Pakistan after Friday prayers to protest the death of Agha Ziauddin, who died from wounds he suffered in an ambush in the town of Gilgit a week earlier.

A demonstration in the capital city, Islamabad, turned violent. Police fired tear gas into the crowd, and several Shi'ite activists were arrested. An unspecified number of people were injured, including protesters and police.

The protesters were calling on the government to track down Mr. Ziauddin's attackers and bring them to justice.

No one has claimed responsibility, but police link the attack to ongoing rivalry between extremists of the Sunni and Shi'ite Muslim sects in Pakistan.

The wounding of Mr. Ziauddin last Saturday sparked sectarian violence in the north of the country that killed at least 17 people and caused damage to government buildings there. The unrest forced the local administration to declare a curfew and call in military troops to keep order.

When Mr. Ziauddin died five days later, authorities widened the area of the curfew, fearing fresh violence. They also reportedly evacuated dozens of foreigners staying in the region.

The unrest comes as the government faces tensions on the other side of Pakistan, in the southwestern province of Baluchistan.

Local tribesmen have been staging repeated rocket and mortar attacks on government targets, disrupting gas supplies from the resource rich area. Several people have died in the clashes between provincial paramilitary forces and tribesmen in the past week.

Among other things, the Baluchistan tribes are calling for the scaling down of the large military presence in the area, which they say undermines their autonomy. Tribal leaders in the largely underdeveloped province also want the government to share income from the gas fields, and to provide jobs to locals on any major projects in the province.

Interior Minister Aftab Sherpao says the government has shown restraint so far and avoided any major military action against the tribes, mainly to protect civilians in the area. But he warns that this policy could change.

"We cannot tolerate further damage and naturally, the law enforcement agencies would retaliate and take punitive actions if these sorts of activities continue," he said.

Provincial paramilitary troops took positions at the major gas fields in the Sui district Wednesday to protect the installations.