KARACHI, Dec 12: Four persons died and three others were wounded in an explosion at a makeshift workshop in Shireen Jinnah Colony on Tuesday evening.

Eyewitnesses said the explosion took place when the mechanic and his helpers were repairing a gear box taken down from a trailer.

Describing the explosion as accidental, CCPO Tariq Jamil told Dawn, that transport workers were handling some piece of iron while repairing the gear box of a truck when explosion occurred.

“Either the iron piece was part of an unexploded landmine or there was some other explosive device that caused the explosion, we are ascertaining the nature of it,” Mr Jamil said.

While returning from Afghanistan, these transport workers often bring iron scrap to dispose it off in the local market, they might have picked up a piece of landmine or some other explosive material which caused the explosion, the city police chief remarked.

He said explosive experts were carrying out investigation at the blast site to reach conclusions.

Another senior police official who visited the site of explosion said there were marks of pellets.

An explosive expert told Dawn that initial findings suggest the transport workers were either using an unexploded shell as a hammer or they were trying to open it. He said it was a high intensity explosion as three persons died on the spot while another later died at the hospital.

Three bodies and two injured were rushed to nearby Dr Ziauddin Hospital where one of the injured was pronounced dead.

Two other victims were taken to Jinnah hospital. One of them, identified as Ziaul Haq, was undergoing operation.

Among the dead were two brothers of Ziaul Haq, Abdul Haq and Alam Zeb. The other deceased were identified as Muhammad Rehman and Suleman.

Later, all bodies were shifted to the Jinnah Hospital for postmortem examination.