KARACHI, 15 April 2006 — Sporadic trouble erupted in Karachi yesterday and traders kept businesses shut after Sunni groups called for a strike to protest the killing this week of 57 people at a religious congregation.

A suicide bomber targeted a gathering of more than 15,000 people celebrating the birthday of the Prophet Muhammad (peace be upon him) at a city park on Tuesday.

Life came to a standstill in other cities also. In Peshawar, Lahore and other cities, all business centers were shut and traffic was off the road. Rallies were held in Karachi, Lahore, Peshawar and the southwestern city of Quetta to condemn the attack. The protesters dispersed peacefully later.

President Gen. Pervez Musharraf has summoned Sindh Chief Minister Dr. Arbab Ghulam Rahim to Islamabad to discuss the Nishtar Park tragedy. Musharraf has ruled out any change in the political setup in Sindh following the blast. “The city is closed and there were reports of some minor skirmishes,” said Salahuddin Haider, spokesman for the Sindh government. “But no major incidents of violence have been reported.”

Some Sunni Tehrik (ST) workers were booked for an alleged attack on New Karachi police. Police said ST activists attacked a police contingent and damaged several vehicles when the body of their leader, Akram Qadri, was brought to his residence in Sector 11-G, New Karachi.

No group has claimed responsibility for Tuesday’s blast and investigators have still to narrow down a list of suspects that includes militant groups as well as Al-Qaeda-linked terrorists.

Buses stayed off the streets after angry young men torched at least three vehicles overnight. They burned tires in some neighborhoods and threw stones at vehicles to force people to heed the strike call.

The Jamaat-e-Ahle Sunnat that organized the Tuesday gathering, called for a countrywide strike to mourn the dead.

Streets in many parts of Karachi were deserted and the situation in many other parts of Sindh province was the same, residents said. Police and other security forces stepped up patrols in parts of the city, including in the vicinity of mosques. “We have deployed an extra 2,500 policemen, in addition to the 5,000 normally on duty, and have increased patrols,” said senior police official Mushtaq Shah. The Karachi stock exchange functioned normally, with the KSE 100-share index closing up 0.63 percent.

Police released a photograph of the bearded, bloodied head of a suspected suicide bomber on Thursday and said a DNA test would be carried out in the hope of identifying the attacker. Police were also questioning a wounded man and looking for an Afghan he said had accompanied him to the park on Tuesday. Several other people had been “detained for debriefing”, said Interior Ministry Secretary Syed Kamal Shah.