Police officials in Karachi suspect that Thursday's attack might be a result of a gang war  [Reuters]

At least 16 people have been killed and several others wounded in a bomb blast in Pakistan's biggest city, Karachi.

Police said they suspected Thursday's explosion was caused by a planted bomb.

"We are gathering details," they said.

Al Jazeera's Kamal Hyder said a bomb squad is seeking to ascertain whether the explosive had been a large bomb or a hand grenade as earlier reports had suggested.

"The attack appears to be linked to the turf war that has been going on for some time and was also alleged to be a gambling den," he said.

"According to some estimates, up to 300 people were at the location at the time of the explosion."

The number of dead is likely to rise, with up to 35 people injured, he said.

No one claimed responsibility for the bombing at the club.

Police officials said that the club was run by criminals and was home to illegal gambling.

"We were gambling. Suddenly there was a loud bang. We could not make out what had exploded. When we reached here then we knew it was a bomb blast," one of the injured told Reuters.

Police suspect that the attack might be a result of a gang war.

Karachi has a long history of blood feuds between rival ethnic, political and sectarian groups, in which hundreds of people have been killed.

Fighters linked to al-Qaeda and the Pakistani Taliban have also carried out attacks in the city in the past.

Source: Al Jazeera and agencies