Islamabad:Nine people, including six policemen, were killed in a double attack in in Pakistan’s northwestern town of Dera Ismail Khan on Sunday.

Unidentified gunmen on four motorcycles first attacked the Kotla Saidan checkpost in a residential area, killing two policemen and fled the scene. Later, a suicide blast took place at the hospital where the victims were shifted. The bomber struck at the entrance of the hospital, killing four policemen and three civilians who were visiting their relatives, local media reported.

About 30 others were injured in the two incidents, police said.

Dawn newspaper cited a local forensics expert who said that the attacker was female and set off 7 kilograms of explosives packed with nails and ball-bearings.

The Tehreek e-Taliban Pakistan armed group claimed responsibility in an emailed statement, saying the attack was “in revenge” for the killing of a commander by police in Dera Ismail Khan.

The statement also said the suicide-bomb attacker was a man and named him as Abu Obaida Ghazi.

Police, however, refused to confirm or deny details about the bomber as the investigation is at an early stage.

Pakistan has been battling the Tehreek e-Taliban Pakistan and its allies since the group was formed in 2007, aiming to impose a strict interpretation of Islamic law in the country.

Dera Ismail Khan is used to be a hotbed of militancy, but terrorism has been curtailed greatly after years of military operation in tribal areas to remove sanctuaries of terrorists. Local analysts believe that the backbone of the militants has been broken, but they still have some resources left to carry out sporadic attacks on security forces and general public.