KARACHI: Gunmen shot five health workers on an anti-polio drive in a string of attacks in Pakistan on Tuesday, officials said, raising fears for the safety of workers immunizing children against the crippling disease.

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Four were killed in three different incidents in the port city of Karachi and the fifth in the northwestern city of Peshawar, on the second day of a nationwide three-day drive against the disease, which is endemic in Pakistan.

All of the victims were Pakistanis working with a UN-backed programme to eradicate polio.

Sagheer Ahmed, the health minister for Sindh province said he had ordered a halt to the anti-polio drive in the city in the wake of the shootings.

The first incident occurred in Karachi’s Landhi area where unknown assailants opened fire upon a polio team, killing two female members of the team. Police told DawnNews that there were no eyewitnesses of the incident.

The relatives of the deceased said there was no police accompanying the polio team when the incident occurred.

The second incident occurred in the Raja Tanvir Colony in Karachi’s Orangi Town area where another polio team was attacked by unknown gunmen. The in-charge of the team, Dr Shafiq, said one female worker was killed on spot while a male worker was seriously injured in the firing. He was shifted to a hospital for treatment where he succumbed to his in juries.

A third polio team, sent by provincial health ministry, was attacked in Mochko area’s Mohammad Khan Colony. One female worker was killed and another male worker was injured in the attack.

The team had received telephone calls warning workers they would regret helping the “infidel” campaign against polio, said health official Gul Naz, who oversees project in the area where the women were shot.

In Peshawar, which lies close to the restive tribal areas, a haven for militants and hotspot for polio, two attackers on a motorbike fired on two sisters working on vaccination, killing one, senior police official Javed Khan told AFP.

The incident took place in Mathra suburb of Peshawar which borders Mohmand tribal district, Khan said.

Hayat blamed “militants who issued a fatwa against polio vaccination in the past” for the Karachi killings.

On Monday, police said a gunman killed a volunteer for the World Health Organization’s anti-polio campaign was shot dead on the city outskirts in Gadap Town.

Earlier in July 2012, a local paramedic associated with the polio vaccination was shot dead and a World Health Organisation doctor, Fosten Dido, from Ghana along with his driver were wounded in two separate attacks in the Sohrab Goth area.

WHO, a partner in government efforts to eradicate the disease, suspended vaccination activities in part of Pakistan’s largest city in July after a spate of bloody shootings.

In July, a local paramedic associated with the polio vaccination was shot dead and a World Health Organisation doctor, Fosten Dido, from Ghana along with his driver were wounded in two separate attacks in the Sohrab Goth area.

Pakistan is one of only three countries where the highly infectious crippling disease remains endemic, along with Afghanistan and Nigeria.