By Subir Bhaumik
BBC News, Calcutta
There has been a surge in Maoist violence in recent months
At least 24 troops were killed when armed Maoists attacked a camp of the paramilitary forces in India's West Bengal state, officials said.
Nearly 50 rebels on motorcycles encircled the camp of the Eastern Frontier Rifles (ERF) at Silda village on Monday and started firing on it.
More fighters joined the assault on foot, firing from automatic weapons.
More than 6,000 people have died during the rebels' 20-year fight for communist rule in many Indian states.
The Indian government recently began a major offensive against the rebels in several states.
Indian Prime minister Manmohan Singh has described the Maoist insurgency as India's "greatest internal security challenge".
The rebels now have a presence in 223 of India's 600-odd districts.
The camp was overrun by the Maoists after the troops put up brief initial resistance, district magistrate of West Midnapore district NS Nigam told the BBC.
"The Maoists then burnt down the camp and planted landmines on the entire length of the road leading to the camp. Reinforcements with night vision and anti-landmine vehicles reached the camp late at night," Mr Nigam said.
At least 24 bodies have been recovered from in and around the camp and some of them are badly charred, he said.
The government has launched a major offensive against the rebels
The seriously injured troops were being taken to the state capital, Calcutta, for treatment. Officials said at least 12 soldiers were still missing.
It took four hours for reinforcements to reached Silda as there were landmines planted on the entire stretch of the road.
Police officials leading the reinforcements that reached Silda late at night said many of the paramilitary troops were shot dead by the rebels as they tried to escape the fire.
West Bengal's police chief Bhupinder Singh said there were nearly 50 ERF troops in the camp when the attack took place.
The Maoists pulled out of Silda after looting a huge amount of weapons from the camp's armoury.
Chief of the rebels' military wing, Koteswara Rao - alias Kishenji - claimed responsibility for the attack.
He said this attack was the beginning of "Operation Peace Hunt", the Maoist answer to the government "Operation Green Hunt" launched against the Maoists recently.
"We are looking for peace but we are forced to fight and kill the poor troops of the government forces. We will mourn the death of those killed but the government is responsible for their death," Kishenji told the BBC by phone from an undisclosed location.
The Maoist leader warned of more such attacks unless Operation Green Hunt was stopped.
Earlier this month Home Minister P Chidambaram held a meeting of four Maoist-affected states - West Bengal, Jharkhand, Bihar and Orissa - in Calcutta.
He threatened to intensify Operation Green Hunt if the rebels did not start talks by abjuring violence.
The Maoists said they would agree to talks if four of their senior leaders now in jail were released and Operation Green Hunt was halted.
The government has not responded to that conditional overture.