Description:Ambulances take away the bodies of health workers in Karachi, Pakistan, shot by gunmen during an anti-polio drive on Tuesday. Three women were killed and one man wounded in seperate shootings. It was not clear who was behind the attack, but Taliban insurgents have repeatedly denounced the anti-polio immunisation campaign as a Western plot to sterilise Muslims. The team had received telephone calls warning workers they would regret helping the "infidel" campaign against polio.(0:58)