Indian police and Maoist fighters have fought a fierce gun-battle deep in the rebels' jungle stronghold.
The violence flared on Wednesday when a security patrol of about 70 men was ambushed by up to 200 Maoist fighters in the central state of Chhattisgarh.
Police said the security patrol came under fire from Maoists perched on a hilltop.
"The policemen were ambushed in a forest by Maoists as they were returning to a police station," Rabndra Nath Chowdury, a journalist with the Deccan Chronicle newspaper told Al Jazeera.
Fighting raged for six hours and contact with the police force was temporarily lost in heavy rain, officials said, raising concerns for their safety.
But on re-establishing contact, police reported no injuries and said they were on their way back from the jungle.
"The gun fight is over and all policemen are safe," Vishwa Ranjan, the state police chief. "They are on (their) way back, but returning very slowly as there is a possibility of landmines or ambushes."
The violence highlights the strong rebel presence in significant portions of India, especially in poor rural regions left out of India's economic boom.
In a separate attack in eastern Jharkhand state on Tuesday, rebels killed five people, police said.
It was not immediately clear why the Maoists killed them.
Security forces launched a counter-offensive against Maoists earlier this year but recent attacks raise questions over how well prepared security forces are to tackle the rebels.
In April, a similar ambush by Maoists killed 75 policemen and a month later a bus bombing killed 35 people, including security forces.
Both attacks occurred in the mineral-rich but largely poor Chhattisgarh state.
Rebels claim to be fighting for the right of poor peasants and landless workers and aim to topple the Indian state by 2050.
They have been described by Manmohan Singh, India's prime minister, as the country's largest internal security threat.
They operate from jungle bases and launch hit and run attacks on police, transportation networks and government buildings in east, central and southern India, where they control large territories.
Thousands have been killed since the insurgency started in the late 1960s and the Indian government has said that Maoist fighters represent the country's most dangerous internal security threat.