Peshawar: Nine security officials and 15 militants were killed while several others sustained injuries in an operation in northwest Pakistan, police said Thursday. The operation was launched in retaliation for an attack on a police check post Wednesday in Hangu district of the restive Khyber Pakhtunkhwa province. According to a police spokesperson, nine police personnel were killed while 28 others sustained injuries during the operation. The intense exchange of fire during the operation also killed 15 militants and injured several others, police said. Khyber Pakhtunkhwa Chief Minister Suhail Afridi condemned the militant attack and sought a detailed report.