PESHAWAR, Pakistan (AP) — A Pakistani health official says two new polio cases have been reported in the country’s northwest despite efforts against the crippling disease.

The announcement came as gunmen killed a policeman escorting polio workers in Buner, a town in the Khyber Pakhtunkhwa province, on Wednesday.

Health official Kamran Ali Afridi, says the two new cases were recorded in the regions of Bannu and North Waziristan the previous day.

Also on Tuesday, gunmen in Bannu killed a policeman protecting polio workers during a three-day nationwide polio drive.

Pakistan regularly carries out anti-polio drives despite threats from the Taliban who claim the campaign is a Western conspiracy to sterilize children.

This week, police arrested a man for spreading rumors that children had fainted after getting the vaccine, in the form of drops.