Gunmen ambushed a Pakistani school bus on the outskirts of the northwestern city of Peshawar on Tuesday, killing four children and a driver in a hail of bullets, police said.
The attack happened in the Matani area close to Pakistan's northwestern tribal belt, which the United States considers the most dangerous region on earth and the global headquarters of Al-Qaeda.
"Gunmen opened fire on a school van and also lobbed a rocket in Peshawar's suburb of Matani," senior police official Ejaz Khan told AFP.
"We are checking why the bus was targeted," he said. The vehicle belonged to the private Khyber School, he added.
Bombings blamed on Taliban and Al-Qaeda-linked networks have killed more than 4,630 people since 2007, destabilising the nuclear-armed state.
There was no immediate claim of responsibility for Tuesday's attack.
"The driver and four children have been killed," Kalam Khan, a senior police official, told AFP from the scene.
"The children are aged nine to 14. Five children are injured," he added.