Doctor Omar Zeb told AFP that 11 people had been brought to the local hospital -- seven primary schoolgirls and four other people who had been outside in the street.
Police official Azad Khan told AFP that at least four girls, two boys and a man had been wounded. Three of them are in serious condition he said.
There was no immediate claim of responsibility but Islamist militants frequently attack girls' schools -- usually when the buildings are empty in the evening or during the holidays.
Last October the Taliban shot schoolgirl activst Malala Yousafzai in the head in the northwestern Swat valley.
She has largely ecovered and now lives in England, where she is enrolled at a private school and has become a global icon for children campaigning for the right to an education.