The insurgents, belonging to United National Liberation Front (UNLF), People's Liberation Army (PLA) and Kanglei Yawol Kann Lup (KYKL), were arrested yesterday.
An AK 47 rifle, 16 rounds of ammunition, one 9mm pistol, and a hand grenade were recovered from their possession.
A PLA sympathiser was arrested from Imphal West district last evening.
Following his interrogation, police recovered two 9mm pistols, some rounds of ammunition, one grenade, two mobile phones and five kgs of explosive materials from a house, they said.