IMPHAL, July 18: Four personnel of the Central Reserve Police Force (CRPF) were killed and a jawan was injured in a well planned ambush laid by suspected Peoples' Liberation army activists at Lamtan under Loktak police station this morning at around 8.30 am. The underground activists took away a loaded self-loaded rifle and an indigenously developed INSAS rifle. A column of the 112 Bn CRPF consisting of 32 personnel on a road opening patrol duty along the Charoi Khullen road was fired upon by the suspected underground activists who waylaid the approaching column at Lamtanjar village. The assailants, numbering about 50 are armed to the teeth with sophisticated weapons rained down bullets on the patrol party killing four of them on the spot and injuring one jawan. The source further said that the activists escaped towards the Chiroi Khullen hill. There is no report of casualties on the side of assailants. A caller who claims to be a spokesman of the Peoples' Liberation Army rang up The Imphal Free Press this evening claiming responsibility for the ambush. Meanwhile, local residents of the Village on hearing the gunfire fled their home to the neighboring Bishnupur Bazar and other adjoining villages. No civilian was however injured in the incident.