A senior health official says gunmen have killed four women working on a government polio vaccination campaign in the Pakistan's largest city, Karachi.
Sagher Ahmed, health minister for surrounding Sindh province, says the gunmen on Tuesday also wounded two men who were with the women.
The Taliban have spoken out against polio vaccination in recent months, claiming the health workers are acting as spies for the US and the vaccine itself causes harm.
Ahmed says the shootings took place in a Karachi area populated by ethnic Pashtuns. The Taliban are a Pashtun movement, and many militants are reported to be hiding in these communities in Karachi.
On Monday, police said a gunman killed a volunteer for the World Health Organization's anti-polio campaign in Karachi.