Gunmen on motorbikes wounded 15 girls when they opened fire with pistols and lobbed grenades at a college party in Northwest Pakistan on Tuesday, the police said.
Some of the victims were in a critical condition after the attack on the state-run girls-only institution in the town of Mardan, 40 kilometres (25 miles) northeast of the regional capital Peshawar.
All the girls were aged 18 to 20, the police said.
"Gunmen hurled two grenades and then opened fire with pistols. Fifteen girl students have been injured, some of them were in critical condition," Khalid Nasim, a senior police officer in the town, told AFP.
An intelligence official in Peshawar said the attackers fled the scene afterwards.
There was no claim for the attack, but Islamists opposed to co-education and advocating sharia law have destroyed hundreds of schools, mostly for girls, in Northwest Pakistan in 2011.