Two female polio workers and a police guard have been killed in the northwest Pakistani province of Khyber-Pakhtunkhwa in the latest in a spate of deadly attacks on the immunization teams.

Police said two gunmen fired at the workers as they gave polio drops to children in the Sheikhabad area of Mansehra district.

Local police chief Muhammad Ejaz Khan said the team was administering polio drops in an Afghan refugee camp and its surrounding areas.

Militants frequently target medical workers involved in dispensing polio vaccinations, claiming the internationally backed immunization program is a cover for spying or sterilizing Muslims.

The attacks have contributed to an increase in polio cases in Pakistan, making the country one of only three in the world where the disease remains endemic.

Based on reporting by AFP and dpa