At least three people were killed Tuesday when gunmen fired on a team of health workers carrying out polio vaccinations in southern Pakistan, police said.
Two women were among the dead, Karachi police official Pir Muhammad Shah said. Two people were injured in the shooting, said doctor Simi Jamali at Jinnah Hospital, where they were being treated, dpa reported.
A three-day vaccination drive was stopped after the attack, federal Health Minister Saira Afzal Tarar said.
No group claimed responsibility, but Islamist militants have targeted polio workers in the past.
More than a dozen health workers taking part in a UN-funded immunization campaign and police officials protecting them, were killed by militants in the past year.
Insurgents accuse health workers of acting as spies for the United States, and claim the polio vaccine is intended to make Muslim children sterile.
The World Health Organization says Pakistan is the only country in the world where the number of new polio cases was on the rise in 2013.