The attacks forced health officials to temporarily suspend a large polio vaccination drive in Karachi, the country’s most populous city, where the disease has been making a worrisome comeback in recent years.
Saghir Ahmed, the health minister for southern Sindh Province, said he had ordered the 24,000 aid workers taking part in the campaign in Karachi to immediately stop work. It was not clear when they would resume.
The shooting represented a brutal setback to polio immunization efforts in Pakistan, one of just three countries in the world where the disease remains endemic. Pakistan accounted for 198 new cases last year — the highest rate in the world, followed by Afghanistan and Nigeria.
There was no immediate claim of responsibility, but Taliban insurgents have repeatedly vowed to target anti-polio workers, accusing them of being spies.
In the tribal areas along the Afghan border, Taliban leaders have issued religious edicts declaring that the United States runs a spy network under the guise of vaccination programs.
That perception was strengthened after the American commando raid that killed Osama bin Laden in June 2011, when it emerged that the Central Intelligence Agency had paid a Pakistani doctor to run a vaccination program in Abbottabad, where Bin Laden was hiding, in a bid to obtain DNA evidence from his family.
Pakistani authorities arrested the doctor, Shakil Afridi, shortly after the American raid, and he has been sentenced to 33 years in prison.
Despite the negative perceptions, the government has pressed ahead with a large polio vaccination campaign, usually conducted in three-day spurts involving tens of thousands of health workers who administer medicine to children under 5.
The shootings on Tuesday came on the second day of the latest drive, which has now been called off in Karachi. After an attack on a United Nations doctor from Ghana in Karachi last July, officials were braced for some sort of militant resistance. But the extent and scale of the attacks Tuesday caught the government by surprise.
In the attacks in Karachi, three teams of health volunteers were targeted in poor neighborhoods: Landhi, Orangi and Baldia Town.
Two female aid workers were killed in an attack in Landhi, according to local news reports. In Orangi, unknown gunmen opened fire on a health team, killing one woman and a male volunteer. Another female worker was killed in nearby Baldia Town.
The Karachi neighborhoods where aid workers were targeted Tuesday are being used as safe havens by militants, who have escaped American drone strikes in North and South Waziristan tribal regions, according to police officials. Security forces regularly conduct search operations in these neighborhoods.
In the northwestern city of Peshawar, gunmen riding a motorcycle opened fire on two sisters who had volunteered to help administer polio drops, killing one.
The attacks on polio workers followed a bold Taliban assault on a major Pakistan Air Force base in Peshawar over the weekend that killed at least 15 people and a militant bomb attack in a nearby tribal village on Monday that killed another 19.
For Pakistan’s beleaguered progressives, the attack on female health workers was another sign of how the country’s extremist fringe would stoop to attack the vulnerable and minorities.
“Ahmadis, Shias, Hazaras, Christians, child activists, doctors, anti-polio workers — who’s next on the target list, Pakistan?” asked Mira Hashmi, a lecturer in film studies at the Lahore School of Economics, in a post on Twitter.
Zia ur-Rehman contributed reporting from Karachi
