Thirteen civilians have been killed in a landmine blast carried out by suspected Maoists in the central Indian state of Chattisgarh, police say.
Four others are said to be seriously injured in the blast which took place in the state's Kanker district.
District police chief Pradeep Gupta said the rebels blew up a jeep carrying a group of traders late on Friday.
Thousands have died in Maoist campaigns across central and southern India in the past 30 years.
The latest attack took place when the traders were returning from a weekly trade fair in a local village.
Mr Gupta told the Reuters news agency that the rebels may have mistaken the traders' vehicle for a police jeep.
Earlier this month, at least six people were killed and 33 injured in two attacks by the rebels in a village in the state's Dantewara district.
The rebels launched attacks on people who they suspected of being police informers.
In February, 25 people were killed after Maoist rebels blew up two trucks carrying civilians.
The Indian government believes that there may be 10,000 armed Maoist rebels in India, correspondents say.
The Maoists have a strong presence in eight of 16 districts of Chattisgarh state.