At least 40 suspected militants and two policemen were killed after fresh violence erupted in northeast India's Manipur late Sunday.

Manipur has been on edge after an explosion of inter-ethnic violence this month killed at least 70 people and left tens of thousands displaced.

The state government official, who did not wish to be named, said that Manipur Chief Minister N. Biren Singh told reporters earlier Sunday that security forces killed around 40 "militants" over the last two days.

"The terrorists have been using M-16 and AK-47 assault rifles and sniper guns against civilians. They came to many villages to burn down homes," local media quoted Singh as saying.

"We have started taking very strong action against them with the help of the army and other security forces. We have got reports some 40 terrorists have been shot dead," Singh was quoted as saying.

A military source confirmed an uptick in unrest and said four people had been killed in the past 24 hours.

"At least three armed miscreants, who were trying to set fire to empty houses, and fired at the security forces when they tried to stop them, died in retaliatory firing," the source told AFP, declining to be named.

"One more armed miscreant was killed in Moreh and three others, including two security personnel, were injured," the source said.

The far-flung states of northeast India – sandwiched between Bangladesh, China and Myanmar – have long been a tinderbox of tensions between different ethnic groups.

The violence in Manipur earlier in May was between the majority Meitei, who are mostly Hindus and live in around state capital Imphal, and the mainly Christian Kuki tribe in the surrounding hills.

The spark was Kuki anger at the prospect of the Meitei being given guaranteed quotas of government jobs and other perks in the form of affirmative action.

This also stoked long-held fears among the Kuki that the Meitei might also be allowed to acquire land in areas currently reserved for them and other tribal groups.

Thousands of troops were deployed to restore order, while around 30,000 people fled their homes for the safety of ad-hoc army-run camps for the displaced. Mobile internet has been cut for weeks.