Officials in northwestern Pakistan say unknown gunmen shot and killed a policeman and wounded another, as they were protecting a team of female polio workers administering vaccines.
Authorities said Wednesday's attack happened in Mardan district of Khyber Pakhtunkhwa. No polio workers were harmed since they were inside the home giving polio drops to children when the attack happened.
This is the latest in a series of attacks on people working on the United Nations-backed vaccination campaign in Pakistan. Last December, gunmen killed nine polio workers across the country. Several more have been killed in attacks since then.
No one has claimed responsibility for the attacks, including the one Wednesday, but in the past, the Taliban has indicated violent opposition to the vaccinations and accused health workers of being spies. There also are rumors in Pakistan that the vaccinations are meant to make Muslim children sterile.
Pakistan is one of only three countries in the world where polio is endemic. The problem is worst in the tribal regions, where Islamist militants are most active.