KHYBER AGENCY - Three personnel of security forces were killed and six others got injured during an attack on their convoy here at Akkakhel area of Tehsil Bara, official sources said on Saturday. In retaliation of the security forces, four militants were also killed and several injured, the sources further added. The sources said that three troops were killed on the spot while six others got bullet injuries during the ambush by the militants. The injured were shifted to a hospital. The deceased and injured were shifted to military hospital. Soon after the incident the forces launched a massive operation in the area, the sources added. Three vehicles were destroyed while two personnel were killed on the spot and eight wounded seriously.