PESHAWAR: The World Health Organisation (WHO) directed its field staff to stop their work in Pakistan after two people were killed and two others were injured when teams  involved in the nationwide polio vaccination drive were attacked in Peshawar, Nowshera and Charsadda in the Khyber Pakhtunkhwa province on Wednesday, DawnNews reported.

A woman from a polio vaccination team and a driver associated with the program were killed during the attack on the team in Charsadda.

Senior government official Syed Zafar Ali Shah said gunmen targeted two other polio teams in Charsadda, but no one was wounded in those attacks.

Earlier, reports had stated that a bystander was injured when unknown gunmen fired at a polio team in Charsadda.

After preliminary news of the first attack, EDO Charsadda had stated that the anti-polio drive would continue in the region, adding that, "such attacks" could not shake the resolve of the government.

Moreover, one volunteer was injured during the attack on a polio team in Peshawar. The injured worker was shifted to the Lady Reading Hospital for treatment.

The attack took place in Peshawar's Khazana area when unknown assailants fired at the team.

Separately, gunmen attacked a polio team working in Nowshera. However, no casualties were reported from that attack.

In the wake of the latest attacks on anti-polio workers, the World Health Organisation (WHO) directed its field staff to halt work in Pakistan.

The field staff should stop its work until further instructions, the WHO said.

There was no immediate claim of responsibility for Wednesday's killings.

Earlier on Tuesday, five health workers involved in the vaccination drive were killed in the cities of Karachi and Peshawar.

Four women were killed in less than an hour in seemingly coordinated attacks in Karachi.

A fifth worker, also a woman, was killed in the northwestern city of Peshawar.

The five workers were killed a day after a man working on a local government-World Health Organisation (WHO) project was shot dead in Karachi.

AP adds:

Tehrik-i-Taliban Pakistan’s spokesman Ehsanullah Ehsan claimed responsibility for the attacks on Tuesday, the Associated Press said in a report on Wednesday.

Pakistan is one of only three countries where polio remains endemic, along with Afghanistan and Nigeria, but efforts to tackle the highly infectious crippling disease have been hampered over the years by local suspicion.