PESHAWAR: Three police men were wounded in an attack by gunmen on a polio vaccination team in Khyber Pakhtunkhwa province. The police officers were guarding the vaccination team when the attack took place in Mir Dara district of the province, local police spokesman Zaheer Afridi said. The attackers managed to escape, Afridi added. Pakistan and neighboring Afghanistan are the only countries in the world where the polio virus still exists. Militant groups often attack polio vaccination teams and police officers assigned to protect them.