Fifteen people were also injured in the first blast in a building under construction, police were quoted as saying. The explosion was reportedly detonated with a timer device.
Police said some persons may still be trapped in the building, the News International reported.
The intensity of the blast shattered windows of nearby buildings. Ambulances rushed to the scene to shift the injured to the nearby General Hospital.
A little while later, another explosion was reported in Lahore, Xinhua news agency said. No further details were available.