Pakistani authorities said they have found bodies of four members of a polio vaccination team who were kidnapped by unknown militants in southwestern Baluchistan province on Friday.
The victims include two polio vaccinators and two security personnel. They were coming back to the city of Zhob after taking part in an immunization campaign when suspected militants kidnapped them. Their bodies were discovered Tuesday.
Meanwhile, in the northwestern part of Pakistan, officials said gunmen ambushed another polio vaccination team Saturday, killing the driver.
Authorities said the attack took place in a restive tribal region near the Afghan border. A second team member was unharmed when the attackers fired at their van.
There has been no immediate claim of responsibility for the attacks.
The two incidents took place ahead of a three-day vaccination drive against polio that began Monday.
Authorities said that attacks on polio vaccinators in Pakistan within the past four years have left nearly 70 people dead, including security personnel escorting the teams during national immunization drives.
The violence has undermined anti-polio efforts in Pakistan, where more than 85 percent of the world's cases were located last year, the World Health Organization said.