Suspected Maoist guerrillas, including some female fighters, killed ten Indian policemen during a landmine ambush in the central Indian state of Chhattisgarh, police said Friday.
The overnight attack came less than a day after another Maoist assault in the state killed five other officers in a gunfight when the rebels raided a police camp.
Indian security forces are struggling to combat the leftist rebels, who are entrenched deep in jungles across a swathe of eastern and northern India.
"The ten policemen were in an anti-landmine vehicle but the Maoists targeted them with a very powerful blast as they were proceeding for patrolling duty," Chattisgarh chief of anti-Maoist operations Ramniwas told AFP.
Ramniwas, who goes by only one name, said the attack took place in Dantewada district, a Maoist stronghold, 480 kilometres (300 miles) south of the state capital Raipur late on Thursday night.
Ankit Garg, senior police official in Dantewada, told AFP that after the blast waiting Maoist rebels opened fire on the vehicle.
"Women cadre of the left-wing group actively participated in the brutal attack," he said. "Forces have been sent to the forest for the search of the perpetrators."
The attack was the latest in a series of strikes on often poorly-trained police battling against the Maoists, who fight to overthrow all state and national authorities.
Last month the Maoist rebels killed and then mutilated nine policemen in a gruesome attack in a remote and forested area of eastern Orissa state near the border with Chhattisgarh.
Seven police were also killed in a landmine attack last month in Dantewada, the same district as the overnight deaths.
Dantewada, a hotbed of Maoist activity, has witnessed a series of deadly Maoist strikes in recent years.
In April 2010, a rebel ambush killed 76 policemen in the bloodiest single attack so far on the security forces.
The Maoist movement, which began in 1967, feeds off land disputes, police brutality and corruption, and is strongest in the poorest and most deprived areas of India, many of which are rich in natural resources.
Some 171 suspected left-wing guerrillas were killed last year along with 713 civilians in Maoist-linked violence compared to the previous year's tally of 591. A total of 285 policemen also died in 2010.
Premier Manmohan Singh has called the insurgency India's main internal security threat and has urged state governments to increase pro-poor welfare measures to help counter the rebels.