( CNN ) -- Two men were killed Friday in attacks on polio teams and their police escorts in Pakistan , authorities said . A policeman was killed and another injured when unidentified gunmen fired on a polio security team in Swabi , in northwest Pakistan 's Khyber Pakhtunkhwa province , District Police Officer Sajaad Khan told CNN . The officers were there to protect polio workers , who have come under increasing attack in the past year . The second victim , a polio worker , was shot dead by unknown men in Jamrud , in Pakistan 's tribal Khyber Agency , a political administration official who asked not to be named told CNN . Pakistani cricketer-turned-politician Imran Khan , who heads the Tehreek-e-Insaf ( PTI ) party , condemned the targeting of polio workers in a statement released by his party . Khan called on Khyber Pakhtunkhwa 's chief minister and the federal government to take `` strong action '' to arrest those responsible and to provide security for polio workers . The PTI party holds the majority of seats in the coalition running Khyber Pakhtunkhwa 's provincial government . Militants have targeted anti-polio campaigns in Pakistan since U.S. intelligence officials used a fake vaccination program to help in their hunt for Osama bin Laden in 2011 . Under cover of the program , the CIA sought to collect DNA samples from relatives of the al Qaeda leader to verify his presence in a compound in Abbottabad . More than 20 polio workers have been killed since July 2012 . Some mullahs have also preached against the polio campaign , claiming falsely that the oral vaccine leaves Pakistani children sterile . Last year , a Taliban commander in northwest Pakistan announced a ban on polio vaccines for children in the region as long as the United States continued its campaign of drone strikes . Pakistan stepped up its eradication efforts after cases spiked in 2011 , but cases continue to be diagnosed . At least 16 cases of polio have been reported this year in Khyber Agency . Polio , which can cause permanent paralysis in hours , remains endemic only in Pakistan , Nigeria and Afghanistan . CNN 's Saima Mohsin and journalist Zahir Shah Sherazi contributed to this report .
A policeman who was providing security to a polio team is killed , police say . Unknown gunmen also kill a polio worker in Khyber Agency , a local official says . - The Pakistani Taliban claim responsibility for the attack on an army hospital and its staff members.