The bomb also lethal chemicals that led to a huge fire after the explosions.
The blast destroyed two multi-storeyed buildings comprising 200 flats. Many people are believed to be trapped under the rubble.
Following the blasts, several vehicles and over 150 shops caught fire.
"So powerful was the explosion that the facades of several apartments facing the site of blast were blown off the buildings. Windowpanes of most of the surrounding buildings turned into smithereens. Even some doors came off the hinges," witnesses told Geo TV.
The injured were taken to Abbasi Shaheed Hospital, Patel hospital and Jinnah Hospital.
