A police officer was killed, and another injured, when unidentified gunmen fired on a polio team's security guards in Swabi, in northwest Pakistan's Khyber Pakhtunkwa province, police officer Sajaad Khan said.
A polio worker was shot to death in Jamrud, an unidentified political administration official told CNN.
Militants have targeted anti-polio campaigns since U.S. intelligence officials used a fake vaccination program in 2011 to obtain DNA samples from relatives of Osama bin Laden. The samples were used to verify his presence at his Abbottabad compound, CNN said.
Opposition party leader Imran Khan condemned the killings in a statement, calling on Khyber Pakhtunkwa leaders to take "strong action" to arrest those responsible and to provide additional security for polio workers.