PESHAWAR- A roadside bomb exploded in Mohmand Agency on Wednesday killing two off-duty polio vaccinators and their relative, officials said.

The blast occurred in Ali Nagar village in the Mohammad tribal district along the Afghan border where Taliban militants are active. The bomb went off near the house of polio vaccinator Mohammad Gul who was out walking with his brother, also a polio worker, and his cousin, although it was not clear whether they were specifically targeted.

“Two polio workers and their cousin were killed in the bomb blast,” local government official Khushhal Khan told AFP. A local security official also confirmed the bombing and casualties. The dead bodies were shifted to tehsil hospital Safi. Soon after the blast, the security forces rushed towards the blast site and cordoned off the area and kicked off search operation, however, no arrest was made till filing this report.

Nobody claimed responsibility for the bombing, but militants have been aggressively targeting immunisation workers across Pakistan. The militants allege polio vaccination is a cover for espionage or Western-conspiracy to sterilise Muslims. Those conspiracy theories gained further traction after the CIA recruited a local doctor to start a vaccination programme during the hunt for Osama Bin Laden which dismayed many aid and health workers.

Some 60 people including health workers and police providing security have been killed in militant attacks on polio vaccination teams since December 2012. Pakistan is one of three countries where polio is still categorised as an endemic viral infection. The other two countries are Afghanistan and Nigeria. The number of polio cases recorded in Pakistan passed 200 for the year last week, a 14-year-high. Officials said 136 of the new cases were recorded in the troubled north-western tribal areas that border Afghanistan.