Media playback is unsupported on your device Media caption Footage from the scene shows the devastating aftermath of the explosion

A bomb explosion in the Pakistani city of Karachi has killed at least 11 people, including several children, and injured at least 24 others.

The bomb, which was hidden in a motorcycle, detonated beside a football pitch in the Lyari neighbourhood during a local tournament early on Wednesday.

No group has said it carried out the attack. Witnesses say many victims were between six and 15 years old.

The target of the attack may have been a provincial minister.

The BBC's Charles Haviland in Islamabad says that Javed Naghori was at the game but was unharmed.

In another attempt to kill him earlier this year several people died.

'Running in panic'

Witnesses said the explosion happened in the packed stadium during the prize-giving ceremony after a late-night match.

"When the match ended, we came out and as soon as we came out there was a blast," Ameer Ali, who was injured in the blast, told Reuters news agency.

"Everyone started running in panic. Many people were hit, which scared everyone," he said.

Several of the boys who died or were injured had been at the game and were wearing football kits.

A local website report said doctors were removing pieces of metal and ball bearings from the wounded.

Pictures from the scene show two massive craters in the ground and a destroyed car and motorbike.

Karachi has long suffered outbreaks of violence, caused by militants or by rival political groups fighting turf wars.

In March, a bomb in Karachi's Abbas Town killed at least 45 people and destroyed several buildings.