Teargas shells and rubber bullets were used as forces tried to bring the situation under control. As the armed mob opened fire, the forces also shot back and a person died in the clashes.
The UN Office for the Coordination of Humanitarian Affairs, or OCHA, said more than 430 people were injured during the same period, which has seen 224 violent incidents in 12 of the country's 18 provinces.
In a video statement, former Congress chief Sonia Gandhi expressed sadness that people were forced to flee the only place they called home and leave behind all that they had built over their lifetime.
The attack, carried out by individuals dressed in olive green fatigues, has further escalated tensions in the region already marred by clashes between the Kuki and Meitei communities.