The rebels have blown up railway tracks in the past, causing derailments
Maoist rebels in India have killed two people and blown up sections of railway track in four eastern states during a two-day strike, police have said.
The Maoists called the strike on Monday in six states to protest against a major offensive by government troops.
The destruction of one section of track in Bihar caused an express train to derail. No casualties were reported.
The rebels want communist rule in a large swathe of India. More than 6,000 people have died in the 20-year fight.
The Maoists say they are fighting for the rights of the rural poor who complain they have been neglected by governments for decades.
Indian Prime Minister Manmohan Singh has described the Maoists as the single biggest threat to India's internal security, and ordered a major offensive in November.
Nearly 50,000 federal paramilitary troops and an equal number of policemen, equipped with helicopters and unmanned aerial surveillance vehicles, are taking part in Operation Green Hunt.
The Maoists called a 48-hour strike in Bihar, Jharkhand, Orissa, West Bengal, Chhattisgarh and Andhra Pradesh on Monday to "protest at the operations against the movement of the common people".
On Tuesday, police blamed the rebels for the destruction of a 1.2m (4ft) section of railway tracks, which caused seven coaches and the engine of an express train to derail.
The incident happened 15km from the town of Gaya in Bihar, while the Rajdhani Express was en route from the city of Bhubaneswar in Orissa to the capital, Delhi, officials said.
Railway spokesman Samir Goswami told the BBC that the rebels had blown up tracks in three other places in Bihar, West Bengal and Orissa, leading to the cancellation of several services.
In Jharkhand state, rebels killed one policeman after a prolonged gun battle with security forces in the Saupuria area, police said.
And in West Bengal state, rebels were blamed for killing a school headmaster, Hemant Pradhan, who was said to be a supporter of the ruling Communist Party of India (Marxist).
Police said Mr Pradhan was dragged out of his home in Sankrail and shot dead.