A Pakistani policeman has been shot dead while protecting a polio vaccination team in the country's tribal region of Waziristan, bringing the death toll for such attacks to 20 since December.
Reports say gunmen opened fire on a polio team near the northwestern town of Mardan on Tuesday.
The local Taliban faction has banned polio vaccinations in the area, alleging the operation is a cover for espionage. There have also been rumors that the vaccinations are an attempt to sterilize Muslim children.
Polio cases have risen sharply in Pakistan in recent years, reaching a high of 198 cases in 2011. Pakistan is one of very few nations left in the world where polio is endemic.