At least 35 people were killed when rebels detonated a landmine under a passenger bus in India.
They included police officers and civilians.
The incident took place in the Dantewada district in the state of Chhattisgarh, where there has been a Maoist rebellion for decades.
The BBC reports Dantewada was the scene of another attack last month when 76 people were killed.
Earlier on Monday, the bodies of six villagers were found with their throats slit in the forests of Chhattisgarh. They were kidnapped at the weekend.
The insurgency has been described by Prime Minister Manmohan Singh as the country's biggest internal security threat.
Last October, the government announced a massive anti-Maoist offensive and deployed 50,000 troops in several states.