A car bombing at a police post killed at least four officers in ​northwestern Pakistan on Saturday and was followed by an ambush on ‌police personnel rushing to the scene to provide backup, local media reported.

Police official Sajjad Khan said most of the 15 officers who were on duty at the post ​on the outskirts of the city of Bannu were feared ​dead and that the installation had been destroyed, according to Reuters.

He added the fighting ⁠was ongoing and the extent of the damage would only be ​known once the operation was over.

“The terrorists first attacked the police post with ​an explosives-laden car, and then militants entered its premises and opened fire on the police personnel,” another police official said, asking not to be identified.

“Other law enforcement personnel ​were sent to help the police, but the terrorists ambushed them and ​caused some casualties.”

Police sources said the militants also used drones in the attack.

Ambulances from ‌rescue ⁠agencies and civil hospitals were dispatched to the scene, with officials saying a state of emergency has been declared in government hospitals in Bannu.

A militant alliance known as the Ittehad-ul-Mujahideen claimed responsibility for the attack.