At least nine people were killed and nine injured when gunmen fired on a truck in the Pakistani port city of Karachi on Saturday evening, police said.
Police Chief Kaved Akbar Riaz said there were more than 20 people in the truck returning from the wedding ceremony at the time of the attack, including women and children.
Karachi hospital doctor Garar Abbasi said five women and four children had died. Riaz said preliminary investigations showed that the attackers followed the truck and then threw hand grenades or improvised explosive devices at one side of the truck.
Nobody claimed responsibility for the attack. Although the cause of the explosion is unknown, the police did not rule out sectarian violence.
Karachi Police Chief Imran Yakub Minhas condemned the attack as a "terrorist act" as Pakistan celebrated its Independence Day on Saturday.
Earlier in the day, Pakistani security forces killed three militants in a shootout following an attack on a security patrol in the southwestern province of Balochistan, the military said.
Military officials say a car bomb exploded at an Iraqi police recruiting office in Kisak, west of Loralay, killing at least one soldier and injuring two others.
No one claimed responsibility for the attack. However, in recent years, Baloch secessionist groups have frequently launched similar attacks.
Baluchistan, bordering Iran and Afghanistan, is rich in minerals.

Rasul