Gunmen open fire at a police officer reviewing security arrangements for polio vaccination team in Pakistan

Unknown assailants on Wednesday opened fire at a police officer who was reviewing security arrangements made for a team of polio vaccination workers in northwest Pakistan, officials said.

District Police Officer (DPO) Muhammad Shuaib, however, escaped unhurt in the skirmish.

Shuaib was reviewing security arrangements for the polio vaccination team at Koi Bhara in Dera Ismail Khan district in Pakistan's Khyber Pakthunkhwa province, when unidentified gunmen opened fire at the DPO vehicle, police said.

Police have launched a massive search operation to nab the culprits.

No group has claimed responsibility for the attack so far.

Pakistan is one of the two polio-endemic countries in the world along with its neighbour Afghanistan.

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

Attempts to eradicate the crippling virus have been seriously hampered by deadly targeting of vaccination teams in recent years by militants, who oppose the drives, claiming that the polio drops cause infertility.