Police said the cadre, identified as 26-year-old Heisnam Shangoi Devi at Moirang Leima was nabbed from her residence at Moirang Siribon Leikai in Bishnupur district of the state.
On investigation it was learnt that she was trained at Sajik Tampak in the state's Chandel district bordering Myanmar and belonged to the 20th batch of the militant group.
One Chinese-made hand grenade was also recovered from the possession of Shangoi Devi.