Gunmen attacked two police officers who were providing security for polio vaccination workers in Pakistan’s restive Khyber Pakhtunkhwa province, killing one and wounding the other, police said on Saturday, days after a major terror group announced that it has ended a month-long ceasefire deal with the government.

Mohammad Khurasani, spokesman for Tehrik-e-Taliban Pakistan (TTP), known as the Pakistani Taliban, claimed responsibility for the attack.

It was the first attack since the TTP on Thursday announced the end of a one-month cease-fire with the government. The truce had been announced in November amid peace talks between the two sides. The TTP has been targeting vaccination drives in Pakistan, claiming it was a western conspiracy to sterilise children.

The assault took place in Tank district in Khyber Pakhtunkhwa province on the second day of a five-day anti-polio drive in the province, a police official said. Two gunmen riding a motorcycle open fire at a police team escorting the polio vaccinators in Chaddarah area, killing one constable and critically wounding another, the official said.

However, members of the vaccination team escaped unhurt, police said. Pakistan is one of the two polio-endemic countries in the world along with Afghanistan. Pakistan has launched a fresh anti-polio vaccination campaign across the province to eradicate the crippling disease.

In 2014, the World Health Organisation had made it mandatory for all people travelling from Pakistan to carry a polio vaccination certificate.

Chief Minister of Khyber Pakhtunkhwa Mehmood Khan has condemned the attack and promised that the culprits will be brought to justice.