Gunmen have shot and killed a police officer assigned to protect polio workers in northwestern Pakistan, officials say.
The office of the deputy commissioner for the Bajur tribal district said that the police officer was on his way to a health center in the village of Dabra on September 24 when he was shot.
A local government official, Anwarul Haq, said that a number of suspects were detained following the attack in Bajur district, which borders Afghanistan.
Taliban militants have killed scores of anti-polio workers in Pakistan in the past decade because they believe vaccination campaigns are part of a Western conspiracy and claim that it will sterilize Pakistani children.
No militant group immediately claimed responsibility for the latest killing, which came amid a weeklong, nationwide campaign aimed at vaccinating 38.6 million Pakistani children under the age of 5.
A three-day anti-polio drive was launched in the northwestern province of Khyber Pakhtunkhwa and the seven tribal districts on September 24, during which more than 6.5 million children were expected to be vaccinated.
Pakistan, Afghanistan, and Nigeria are the only countries in the world where polio is still endemic.
A UN-funded vaccination campaign has helped Pakistan to control the spread of the disease. The number of newly affected children came down to only four so far this year compared to 306 in 2014.