One person was killed and over a dozen injured in an explosion in Pakistan's commercial capital Karachi on Thursday night, police and health officials said. 

An improvised explosive device (IED) which was planted in a motorbike went off on a crowded street in the city's downtown Saddar area, Asad Raza, a senior police official, told reporters.

Four of the 13 injured are in critical condition, said Dr. Shahid Rasool, head of the Jinnah Postgraduate Medical Center.

Several vehicles and motorbikes parked at the site were also damaged in the blast.

There was no immediate claim of responsibility for the explosion.

Footage aired on local broadcaster Dawn News showed panicked pedestrians taking cover on adjoining streets soon after the blast as several vehicles caught fire.

Honking ambulances were seen arriving on the scene to transport the injured to the hospital.

The blast occurred a couple of weeks after a suicide bombing at the University of Karachi that killed four people, including three Chinese nationals.

The outlawed Balochistan Liberation Army, which has been fighting for the succession of mineral-rich Balochistan province, claimed responsibility for the terrorist attack./aa