GAUHATI, India — An insurgent separatist group has claimed responsibility for a weekend attack in India's remote northeast that left four Indian paramilitary soldiers dead.

The National Socialist Council of Nagaland (Khaplang) emailed reporters to say it was behind the Sunday attack, in which insurgents attacked a passing security convoy with automatic weapons and hand grenades.

The attack was part of an offensive "to sanitize the land against the illegal deployment of occupational Indian forces," said the statement, which was signed by Isak Sumi, the group's spokesman.

The group has been fighting for an independent homeland for the Naga tribe. It ended peace talks with the Indian government in 2015 after 14 years of futile negotiations.

On Monday, an emailed statement from Ulfa (Independent), another of the region's myriad separatist groups, said it had worked with the Naga militants to carry out the attack.

The attack occurred near the village of Aboi, about 400 kilometers (250 miles) east of Gauhati, the largest city in India's northeast.

In 2015, the Naga group ambushed an Indian army convoy in Manipur state, killing 18 soldiers in their worst attack in two decades. Since then, the army has stepped up operations against the group.

India's northeast, where most people have ethnic ties closer to China or Myanmar than to the rest of the India, is home to dozens of militant separatist groups, ranging from heavily armed militias to tiny splinters movements.

Northeast separatist groups accuse the Indian government of exploiting the region's rich natural resources while neglecting local development.