At least 180 people have died since fierce fighting broke out between members of the majority Meitei and minority Kuki communities in the state in May, following a court order suggesting privileges granted to Kukis also be extended to Meiteis.

Three people were killed and five injured when gunmen in camouflage fatigues opened fire in the Lilong area of Thoubal district on Monday. Separately, at least seven security personnel were critically injured in an ambush by foreign mercenaries on Tuesday, officials said.

The injured security personnel were part of a convoy travelling through the town of Moreh, bordering Maynmar, that was attacked with rocket-propelled grenades and other automatic weapons.

"Four police commandos and three BSF (Border Security Force) troopers are now in a critical condition," a police official told Reuters on condition of anonymity.

Manipur chief minister N Biren Singh said the assailants were suspected of being "Myanmar-based mercenaries", and added that the government "will not succumb to this kind of pressure".

There was no immediate word on the identities of the three people killed on Monday or the suspected identities of the assailants.

Authorities have re-imposed an indefinite curfew in Thoubal district and four other adjoining districts of Imphal East, Imphal West, Kakching and Bishnupur since late on Monday.

Manipur, bordering Myanmar, is among the smallest states in India with a population of 3.2 million.

Of its residents, 16% are Kukis, who live in the hills and receive economic benefits and quotas for government jobs and education, while 53% are Meiteis, who control the more prosperous lowlands.

(Reporting by Zarir Hussain, writing by Sakshi Dayal; editing by Raju Gopalakrishnan and Barbara Lewis)