Up to five people are reported to have been killed in a bomb blast that hit a bus taking Pakistani navy employees to work on April 28 in the southern port city of Karachi.
It was the third such attack this week.
The dead included four navy personnel and a passing motorcyclist. More than a dozen people were wounded.
On April 26, four people were killed in bomb attacks on two buses carrying Pakistani naval staff in Karachi.
The Pakistani Taliban has claimed responsibility for all three attacks, and warned of more strikes unless security forces halt measures against Islamic militants in Pakistan's northwest, close to the Afghan border.
Karachi is Pakistan's biggest city, main economic center and home to the main base of the Pakistani navy.
compiled from agency reports