In a raid conducted on Tuesday evening the police rounded up one militant of the PLA at Heirok in Thoubal district. He was identified as H. Radhesyam.
Acting on intelligence inputs, police of the Imphal east district also raided some localities on Monday night.
Three more militants of PLA from Khurai areas in the district were arrested. They were identified as T. Arun, R.K. Surjit and N.Premchand.
Three loaded 9mm pistols with magazines, three Chinese made hand grenades and mobile phones were recovered from their possession, police said.
Two separate cases have been registered and investigation is on, they said.