Angry villagers in India torched army vehicles in protest in the country’s remote northeast region along the border with Myanmar after the army gunned down at least 15 people believing that they were militants, officials said on Sunday. Nagaland state’s top elected official Neiphiu Rio ordered a probe into the killings, which occurred on Saturday. “The unfortunate incident leading to the killing of civilians at Oting is highly condemnable,” he tweeted, says a media report. An army officer said the soldiers fired at a truck after receiving intelligence about a movement of insurgents in the area and killed six people. As irate villagers burned two army vehicles, the soldiers fired at them, killing nine more people, the officer said on condition of anonymity, Earlier the officer had said seven protesters were killed. One soldier was also killed in the clash with protesters, he said. An Indian army statement said it “deeply regretted” the incident and its aftermath, adding that “the cause of the unfortunate loss of lives was being investigated at the highest level and appropriate action will be taken as per the course of law.” “Security forces have suffered severe injuries in the incident, including one soldier who succumbed to the injuries,” it added. The statement said “credible intelligence” on insurgent movements indicated that a “specific operation was planned” in Mon district in Nagaland. Nyamtow Konyak, a local community leader, said those killed were coal miners. India’s Home Minister Amit Shah expressed anguish over the “unfortunate incident” and said the state government will investigate the killings. The army officer said the soldiers had laid an ambush for a week following intelligence that insurgents were planning to attack soldiers in the area, 400 kilometers (250 miles) east of Gauhati, the capital of Assam state. Nagaland Chief Minister Neiphiu Rio appealed for calm and announced an investigation into the event. “The unfortunate incident leading to killing of civilians at Oting, Mon is highly condemnable,” he said on Twitter. “Appeal for peace from all sections.” Mon district is about 220 miles (350 kilometers) from Nagaland’s capital Kohima, and is more than a day’s drive only along poorly maintained roads.Senior state, police and army officials had reached the district to investigate, a senior state government official, who asked not to be named, told AFP. The region is home to dozens of tribal groups and small guerrilla armies whose demands range from greater autonomy to secession from India. Over the years, insurgency has waned, with many groups striking deals with New Delhi for more powers, but a large Indian garrison remains stationed in the region. Congress leader Rahul Gandhi also attacked the Centre over the killing of civilians, saying the government must give a “real reply” as to what is the home ministry doing when “neither civilians nor security personnel are safe in our own land”. Local organisations have demanded action against the guilty personnel and threatened to approach national and international human rights organisations. Members of the victims’ families refused to receive their bodies if justice is not delivered fast. Reacting to the incident, the Eastern Nagaland People’s Organisation (ENPO) announced the withdrawal of six tribes it represents from the annual Hornbill Festival ongoing at Kisama near State capital Kohima. The ENPO had a few months ago adopted a resolution against bloodshed in its area. “How can we dance at the festival when our people are getting killed?” the ENPO said in a statement.