PESHAWAR - A policeman was killed and another injured when a polio immunisation team came under attack by unidentified armed men in Dera Ismail Khan district on Tuesday, police said.According to details, a polio team was administering polio drops to children in Parawa area of Dera Ismail Khan, when unidentified men equipped with arms attacked them. A police constable, guarding the polio team, was killed and another head constable Tanveer injured.The polio workers, however, remained unhurt in attack, Parawa Police Station officials said. Police rushed to the spot, cordoned off the area, and mounted a search operation. .The injured policeman was shifted to the district headquarters hospital.Pakistan is one of only three countries in the world where polio remains endemic, along with Afghanistan and Nigeria. Efforts to eradicate it have been seriously hampered by the deadly targeting of vaccination teams in recent years.Militant groups see vaccination campaigns as a cover for espionage, and there are also long running rumours about polio drops causing infertility. According to the WHO, Pakistan recorded 91 cases of polio last year compared with 58 in 2012. Recently, WHO has declared Peshawar as the world’s largest reservoir of polio virus in the world.Agencies add: Some officials, however, said that the policeman was killed ‘mistakenly’ and another wounded by gunfire during the polio vaccination campaign.“A policeman was killed and another was wounded during a door-to-door polio vaccination campaign,” senior police official Nisar Marwat told AFP.“It was not an attack against the anti-polio team. When the team was arriving in the area tribesmen were fighting with each other, and on seeing policemen they thought they were coming to arrest them and they opened fire.”Imtiaz Khan of the Khyber-Pakhtunkhwa provincial health department, who is overseeing the anti-polio drive, told AFP the shooting would not affect the inoculation teams.“The firing incident did not disrupt the anti-polio campaign in the province as the policemen guarding the health workers were mistakenly targeted by tribesmen,” Khan said.This news was published in The Nation newspaper. Read complete newspaper of 12-Feb-2014 here.