The DIG Operations, Karachi, Fayyaz Leghari, is reported to have said that the device was packed in a plastic shopping bag.
He said that those who were killed and injured were employees of the rent-a-car service office.
Edhi sources identified the dead as Rehmat, 20, and Qadeer, 25. The injured were identified as Munawar, Mohammed Aman and Khadim. They were taken to Jinnah Postgraduate Medical Centre for treatment.