Two bombs exploded within minutes of each other in a western neighbourhood of Karachi yesterday, killing at least eight people and wounding more than 50, police and witnesses said.

The bombs were attached to two motorcycles parked outside a roadside restaurant - owned by a big religious school located next door to it, police said.

A police station is also located nearby, they said. A bomb disposal squad defused a third bomb moments before it was to explode, Karachi Police Chief Tariq Jameel said.

"First there was a small explosion, which was followed by a bigger blast," he told Reuters.

Doctors and police said eight people were killed and more than 50 injured were taken to at least three state-run hospitals.

Most of the victims were students of an Islamic school, who frequented this restaurant.

Fayyaz Leghari, a deputy inspector general of police, called the bombing "an act of terrorism."

"The target was the general public and students. The aim was to create chaos," he said.