An assistant commandant of the Cobra battalion, Manoranjan Singh, was also killed while a few troopers were reported to be missing.

Officials said that the Maoists, who had developed a base in 40,000 sq km Bastar region in the late 1980s, were seen running for cover in their own stronghold when Cobra battalion put them under relentless attacks throughout the day.

Maoists, who claim to be fighting for the rights of poor farmers and landless labourers, are expanding their influence in the rural areas of east, central and southern India.

Thousands have been killed in the Maoist insurgency that began in the late 1960s and which Prime Minister Manmohan Singh has described as one of the gravest threats to India's internal security.