IMPHAL, July 30: Four security personnel including a Lieutenant Colonel were killed while as many Assam Rifles personnel were injured in an ambush today by suspected militants near Mao bordering Nagaland on the National Highway 39, reports UNI. Police said the victims were Lieutanant Colonel PNT Nair, Havildar KL Singh, Havildar Hara Prabhu and driver TM Mathew. Four others who were injured in the ambush were hospitalised at Jakhama Army hospital of Nagaland. They were identified as Karna Bahadur, Asok Kumar, Dipak Singh and Hiran Kumar. Police said the militants ambushed when a column of Assam Rifles in three vehicles came towards Imphal from Dimapur. The ultras with sophisticated weapons volleyed a number of bullets when the vehicles of the Assam rifles was passing through a sharp curve of the road in between Tadubi and Chakuma of Mao area. This was the first ambush on the security forces by the underground in Mao area after signing of a ceasefire deal between the Centre and the NSCN(IM).