ISLAMABAD, April 30 (Xinhua) -- One soldier and one police official were killed, while several others were injured in a militant attack on a security check post in Pakistan's northwestern Khyber Pakhtunkhwa province early Thursday, official sources said.

The incident occurred at around 02:10 a.m. local time (2110 GMT Wednesday) when unidentified militants opened fire using small and heavy weapons on the check post in Lakki Marwat district of the province, the sources told Xinhua on condition of anonymity.

Security forces retaliated promptly, triggering an exchange of fire that continued for about 20 minutes, the sources added.

The injured were shifted to a nearby hospital.

Security forces have launched a search operation in the area to track down the assailants.

No group has claimed responsibility for the attack so far. ■