Pakistani troops deployed to streets of this southern Pakistani city Thursday to try to curb rioting and vandalism that flared for a third straight day following a suicide bombing that killed 57 people at a Sunni Muslim prayer service.

Pakistani police officers detain angry protests during a clash a day after the suicide bombing, Wednesday, April 12, 2006 in Karachi, Pakistan. Mobs of youths rioted in Karachi for a second straight day to protest the suicide bombing that killed at least 57 people, which a top Pakistani official said was aimed at 'eliminating' the leadership of a moderate Sunni Muslim group. [AP]

Dozens of youths burned at least two public buses and a car and hurled stones at police forces in various parts of Karachi, said Kazim Ali, the chief of Karachi's fire brigade.

A day earlier, a group of youths rampaged through a neighborhood, setting fire to a bus and two cars and smashing shop windows before police aided by Islamic clerics brought the situation under control, police said.

The troop deployments, the first here since Shiite-Sunni unrest in the early 1990s, took place hours before mass funerals were expected Thursday for three leaders of the moderate Sunni Tehrik group who were among the 57 people ¡ª including the suicide bomber ¡ª killed in Tuesday's attack, one of Pakistan's deadliest ever.

An Associated Press reporter saw an army truck packed more than two dozen brown-uniformed soldiers patrolling Karachi's southern suburbs, the stronghold of the Tehrik group where much of the violence has taken place.

Karachi police chief Niaz Siddiqui said security forces were on high alert for the evening funerals, which are expected to draw tens of thousands of mourners.

"We are deploying troops in the city at sensitive places and if needed the troops will help the civil administration in maintenance of peace and order," said Col. Idrees Malik, a Pakistan army spokesman in Karachi.

Officials have said that Tuesday's bombing was aimed at wiping out the leadership of Tehrik, a rising Sunni Muslim political force.

"It was a suicide attack and part of a hatched conspiracy to eliminate (Tehrik's) leadership," Information Minister Sheikh Rashid Ahmed said Wednesday.

Leaders from about a dozen Sunni groups have called for a countrywide general strike on Friday ¡ª the Islamic sabbath ¡ª to protest the bombing, said Mufti Muneebur Rahman, a senior Sunni cleric.