Eleven paramilitary officers guarding a team of health workers carrying out polio vaccinations in Pakistan's northwest Khyber Pakhtunkhwa province were killed when their vehicle was hit by an IED explosion.
No one has claimed responsibility for the attack.
This latest attack comes at the start of a month-long ceasefire announced by the armed group Pakistan Taliban.
Al Jazeera's Osama Bin Javaid reports from Islamabad.
Source: Al Jazeera