Sakhiullah Tareen, a former inspector general of police in the area, was killed and his son and a daughter-in-law were injured when gunmen ambushed their car Wednesday near Gilgit town, about 240 kilometers (150 miles) north of the capital, Islamabad.

No one has claimed responsibility, and no motive was immediately clear for the slaying of Tareen, a Sunni Muslim.

Mohammed Hanif, a doctor at a state-run hospital in Gilgit, said on Thursday that four police guards also were killed in the shooting. “They were dead when they arrived at the hospital,” he said.

Intelligence officials had initially reported that only Tareen died and that some police guards were injured.

A senior government administrator in Gilgit, Sajid Baluch, said on Thursday that it would be premature to blame anyone for Tareen’s death.

Tareen served as police chief in the Himalayan region until he was sacked on March 18, weeks after gunmen shot dead Agha Ziauddin, a prominent Shiite Muslim cleric in Gilgit. News reports said the government decided to replace Tareen after he allegedly failed to maintain peace in the town.

The Jan. 8 attack on Ziauddin triggered violence in Gilgit that left 15 people dead. Ziauddin’s Shiite supporters went on a rampage, torching buildings and clashing with rival Sunni Muslims. Many of those who died in the violence were Sunnis.

While most of Shiites and Sunnis live peacefully with each other in Pakistan, small groups of extremists groups from both sects are blamed for attacking each other.

The unrest in Gilgit was controlled after authorities imposed a curfew and called in army and paramilitary troops. The curfew was lifted several days later, but troops still maintain road blocks in the town, where other incidents of sectarian violence have been reported in the past.

The troops have been ordered to increase patrolling and to search vehicles for weapons, Baluch said.

“We tightened security to prevent the situation from deteriorating,” he said.

Meanwhile, shops were shut in a Sunni-dominated district in Giglit after a Sunni group used mosque loudspeakers to urge businesses to close to mourn Tareen’s killing.