Suspected Taliban militants have killed three Pakistani intelligence officials in the country's northwest.

Pakistani police say the gunmen ambushed a vehicle carrying intelligence personnel on Wednesday, opening fire from various directions on a road in the Bannu district of Khyber-Pakhtunkhwa province.

One other intelligence official was wounded.

Bannu is close to Pakistan's restive tribal region, a stronghold of al-Qaida and Taliban-linked militants.