A principal was killed in a hand grenade attack at a school in Karachi's Baldia Town on Saturday, said police.
According to the police, four students were injured in the attack that took place when a prize distribution ceremony was underway at the institution.
The attackers also opened fire inside the school.
The principal, Abdur Rasheed, was an activist of the Awami National Party.
He was reportedly receiving threats for not paying extortion money, local media reports said.