Suspicion for the attacks has fallen on the Pakistani Taliban because of their virulent opposition to the polio campaign, but the group's spokesman, Ahsanullah Ahsan, denied responsibility in a telephone call to The Associated Press. Police say they have killed two militant suspects and arrested a dozen others in connection to the attacks but did not say whether they were Taliban.
Militants accuse health workers of acting as spies for the U.S. and claim the vaccine makes children sterile. Taliban commanders in the troubled northwest tribal region have also said vaccinations can't go forward until the U.S. stops drone strikes in the country.
Insurgent opposition to the campaign grew last year after it was revealed that a Pakistani doctor ran a fake vaccination program to help the CIA track down and kill al-Qaida founder Osama bin Laden, who was hiding in the town of Abbottabad in the country's northwest.
