New Delhi: At least four hardcore Maoists including a woman maoist have been killed in encounter with the forces. The exchange of fire took place in the West Singhbhum district today morning. According to sources, the four Naxals including one zonal commander, one sub-zonal commander and one area commander were killed during an encounter, while two including an area commander arrested in Chaibasa today. A large amount of fire arms including rifles of different calibre have been recovered.