The Army on Sunday ordered a Court of Inquiry into the killing of several civilians during an anti-insurgency operation in Mon district of Nagaland and expressed deep regret over the incident.
Police in Nagaland's capital Kohima said at least 11 civilians were killed by security forces and that it is investigating whether the incident was a case of mistaken identity.
In a statement, the Army said the cause of the "unfortunate" loss of lives is being investigated by the Court of Inquiry at the "highest level" and appropriate action will be taken as per the course of the law.
Official sources said Defence Minister Rajnath Singh and Army Chief Gen MM Naravane have been briefed about the incident.
Army officials said the operation in Mon district that borders Myanmar was carried out based on credible intelligence inputs about the likely movement of insurgents in the area.
"The incident and its aftermath are deeply regretted. The cause of the unfortunate loss of lives is being investigated by a Court of Inquiry at the highest level and appropriate action will be taken as per the course of law," the Army said in a statement.
It said the security forces have suffered severe injuries in the operation and one soldier succumbed to injuries.
Nagaland Chief Minister Neiphiu Rio described the incident as "highly condemnable".
"The unfortunate incident leading to killing of civilians at Oting, Mon is highly condemnable. Condolences to the bereaved families & speedy recovery of those injured," he tweeted.
"High level SIT will investigate & justice delivered as per the law of the land.Appeal for peace from all sections," Rio said.