Polio vaccinations were put on hold in Pakistan's northwest on Tuesday after a female polio worker was killed by gunmen, according to the Associated Press.
The attack in in Kaggawala village near Peshawar also wounded another female worker, police officer Mushtaq Khan told AP.
The violence stopped the United Nations-backed vaccination drive in the country's northwest just hours after it begun.
China's Xinhua, citing local media, said the second female victim later died of her injuries.
Government official Habibullah Arif told AP the government on Tuesday suspended the four-day campaign there "for security reasons and to express solidarity with the slain and injured female polio workers."
No group has claimed responsibility for the attack, but police official Shafiullah Khan told AP that authorities are searching for two gunmen who reportedly fired at the women.
Attacks on polio workers in Pakistan are not uncommon, complicating vaccination work there.