Indian forces have been battling Maoist rebels in the region
At least 11 Indian police officers have been killed in a landmine attack by suspected Maoist rebels, police say.
They were travelling home from duty in the central state of Chhattisgarh when their truck was ambushed, followed by shooting between rebels and police.
The region is part of the so-called red corridor - an area of Maoist activity stretching from Nepal in the north to West Bengal in the east.
Maoist-linked violence has killed 6,000 people in India over two decades.
Seven rebels were killed in the gunfire, Reuters news agency reported.
At least 11 policemen were injured in the blast in Tongapal, about 500km (300 miles) south of the state capital, Raipur.
Last week in the neighbouring state of West Bengal, Indian security forces clashed with protesters in the Lalgarh region where Maoist rebels have taken control.
Hundreds of baton-wielding police charged and fired tear gas shells at a crowd of almost 3,000 in Pirakata.
The state government called in more than 1,000 paramilitary troops to retake the area after police fled.