Officials in southern Pakistan say men armed with guns and grenades have attacked a school, killing the principal and wounding at least six children.

Authorities say the children, between the ages of five and 10, were attending an awards ceremony Saturday at a school in Karachi’s Ittehad Town neighborhood when the attackers struck.

There was no immediate claim of responsibility.

Karachi has been the scene of scores of bomb and gun attacks in recent years, most blamed on militants.

In northwestern Pakistan Saturday, officials say a suicide bomber killed a policeman and wounded six other people.

Authorities say the attack happened about 50 kilometers northeast of Peshawar, the capital of restive Khyber Pakhtunkhwa province, which borders Afghanistan.

There has been no immediate claim of responsibility for the attack, but the Pakistani Taliban has carried out many bombings in Peshawar, targeting security forces and civilians.

Peshawar is located on the border with Pakistan’s semiautonomous tribal region, the main sanctuary for Taliban militants in the country.