Attackers targeted a truck in the Pakistani port city of Karachi on Saturday evening, killing at least nine people and wounding nine others, police said.
Javed Akbar Riaz, a senior police officer, said over 20 people, including women and children, were in the truck returning from a wedding ceremony when the attack happened. Five women and four children were killed, said Qarar Abbasi, a doctor at Karachi's main hospital.
Riaz said an initial investigation suggested the attackers followed the truck and then threw hand grenades or some sort of improvised explosive devices at one side of the truck.
No one immediately claimed responsibility for the attack. The motive for the bombing was not known, though police were quick to rule out sectarian violence.
Karachi police chief Imran Yaqub Minhas denounced the attack as an "act of terrorism" as Pakistan marked Independence Day on Saturday.
Earlier in the day, Pakistani security forces killed three militants during a shootout following a militant attack on a security patrol in the restive southwestern Baluchistan province, the military said.
In a brief statement, the military said there was an exchange of gunfire after militants opened fire on a security vehicle near Shahrig in the Loralai district. One soldier was also killed and two were wounded during the exchange.
No one claimed responsibility for that attack, either, but Baluch separatist groups have often claimed such attacks in recent years.
Baluchistan has been the scene of frequent militant attacks and a long-running insurgency by groups seeking independence for the mineral- and gas-rich province bordering Iran and Afghanistan. The Pakistani Taliban also have a presence there.
