A car bomb in central Pakistan has killed at least 40 people and injured dozens others, in what what appears to be part of rivalry between militant Muslim sects. The government says it is sending in the Army to protect the city against further violence.

The car bomb exploded early Thursday at a religious gathering of several thousand people in the central Pakistani city of Multan.

Witnesses say the blast hit as activists of a radical Sunni Muslim group were attending a night-long meeting to mark the first anniversary of the assassination of its leader, Azam Tariq.

Regional police chief, Talat Mehmood Tariq, tells VOA that a remote-controlled device was used. "When the meeting was over and people were dispersing, there was a car of which we have found some parts, and a very loud and a very strong explosion took place in that car and the car was blown into pieces," he said.

Mr. Tariq says an investigation is under way but he dismisses suggestions it was the work of a suicide bomber. "We have not found any evidence because up till now because absolutely no trace of any dead body in that car has been found out," he said.

Witnesses say 22 people were instantly killed in the attack. Doctors in Multan hospitals are struggling to save scores of injured people.

No one has claimed responsibility for the bombing on the Sunni Muslims. But it comes six days after a suicide bomber killed 31 worshipers from the minority Shi'ite Muslim community in the eastern city of Sialkot.

Militants from both the Islamic sects are blamed for killing each other's leaders and activists. The sectarian violence has left hundreds of people dead.