A bomb blast killed three people and injured five others in Pakistan's southern port city of Karachi early Friday, police said, dpa reported.
Up to 2 kilogrammes of explosives were detonated outside the office of a cable television operator in Landhi area of the country's biggest city and commercial centre, police officer Naeem Broka said.
There was no immediate indication that the business was targeted, as the owner "has denied receiving any threats," Broka said.
A police officer was among the dead, but it was not clear whether he was on duty at the time.
An employee of the office was about to check an unattended bag when the bomb went off, an unnamed witness was quoted as saying by television reports.
The explosion appeared to have been triggered by remote control, Broka said.
Karachi has a long history of ethnic, criminal and political violence, which has seen a spike in recent months.