The attack occurred outside the Kamra air force base in Attock district, about 65 km from the federal capital. The suicide attacker was blown to pieces, the army said.

The bus was taking a group of children to school when it was attacked, military spokesman Maj Gen Waheed Arshad said adding the driver and the guard were seriously injured.

The quick reaction by the driver saved the children, he said.

Kamra is home to the Pakistan Aeronautical Complex, a facility that maintains, assembles and manufactures aircraft for the air force.

The attack came a day after a suicide bomber rammed an explosive-laden SUV into a police check post in the northwestern Swat valley, killing 10 people and wounding at least half a dozen others. Several children were among the dead in this attack.