Police say four people are in critical condition, investigation is under way and the entire area has been cordoned off.
The blast has damaged the windowpanes of nearby buildings in Johar Town. A car and a number of buildings have also been damaged by the blast near Shok Chowk.
The initial report suggests that it is a remote-controlled bomb blast that was foiled to hit the 'real target'.
Police and rescue workers have reached the spot and started operation.
According to the rescue workers, it was gas pipeline that exploaded and cuaused damage.
But there was witness woman who contradicted the rescue workers, saying that blast took place inside a motorcycle that damaged the nearby buildings.
The police have been investigating the matter, forensic experts have also reached there and the place of incident have been cordoned off.