The police said the soldiers resorted to “indiscriminate and disproportionate firing” when they shot at miners, mistaking them for militants.

Six miners were killed in the firing last December near the Myanmar border.

The shootings in the Mon district was the deadliest spell of violence in years in Nagaland, which has long been roiled by an insurgency led by local militant groups.

The Indian army has since apologised for the killings and ordered its own investigation.

But protesters in the state have been also pressing for the government to repeal the Armed Forces Special Powers Act (AFSPA), a controversial federal law that gives the army sweeping powers, including protection from prosecution for soldiers who mistakenly kill civilians.