Geo News said the blast took place in Al-Asif Square area in the suburb of Sohrab Goth.
The explosive device was planted on a motorcycle parked in front of a vacant building near a mosque.
Security officials searched the blast site for more explosives.
Islamabad: At least three people were killed and four others injured Wednesday in a bomb blast in Pakistan's port city of Karachi, a media report said.
First Published: Wednesday, January 30, 2013, 22:19