Militants kill four polio workers in Pakistan

Gunmen killed three Pakistani women polio workers and their driver on Wednesday, police said, in the most deadly attack on the health workers in two years.

Teams in Pakistan working to immunize children against polio are often targeted by Taliban militants, who say the campaign is a cover for Western spies, or accuse workers of distributing vaccines designed to sterilize children.

The women were attacked on their way to meet a police escort, said police official Asad Raza in the southwestern city of Quetta.

"Two men on a motorcycle intercepted the van and shot the occupants using a handgun," he said.

Polio cases this year stand at a 15-year high of 265 in Pakistan. The disease, which can kill or paralyze a child within hours of infection, had been eradicated everywhere else, except for Nigeria and Afghanistan.

One reason for the spike in Pakistan is a military campaign in North Waziristan, a rugged region on the Afghan border, that forced a large number of unvaccinated children to flee their homes and move around the country in June.

An international monitoring body also blamed Pakistan's government in a report last month. Vaccinators rarely get paid their government stipends, while police protection teams often turn up late, if at all.

The complacency of Pakistan's government was "disastrous", the report said, warning that the country risked reinfecting the rest of the world. Pakistan has already exported the virus to Syria, China, Israel and Egypt.