A suspected bomb attack by Maoist rebels killed 16 paramilitary troops in western India on Wednesday, police said.
"Maoists attacked a team of commandos travelling in a private vehicle to inspect an earlier attack. So far 16 men have died," an official at police headquarters in Maharashtra state told AFP.
"More teams have been sent to site for rescue and combat operations," said the officer, who did not want to give his name, AFP reported.
India is holding elections and attacks by Maoist rebels, who are active in several states, often spike as the country goes to the polls.
A second police official put the death toll in the latest incident in the Gadchiroli region of Maharashtra at 15.
"Maoists torched over 30 vehicles in Gadchiroli today at 0700 GMT. In another blast, 15 security officers were killed and rescue operations are ongoing to ascertain the damage," Gadchiroli police official Prashant Dute told AFP.
Indian forces have been fighting Maoists rebels for decades in several areas, in an insurgency that has killed tens of thousands.
The Maoists are believed to be present in at least 20 Indian states but are most active in Chhattisgarh, Odisha, Bihar, Jharkhand - and Maharashtra.
India's nationwide election began on April 11 and runs until May 19.
Last weekend rebels opened fire on Indian police, killing two constables and wounding a villager in the central state of Chhattisgarh, the Press Trust of India (PTI) news agency reported.
One constable and an assistant constable died at the scene and the villager, shot in the chest, was taken by local residents for treatment, PTI reported.
A roadside bomb attack on a political convoy in early April killed five people in Chhattisgarh, two days before the world's biggest election began.
Prime Minister Narendra Modi on Wednesday swiftly condemned the latest attack.
"Strongly condemn the despicable attack on our security personnel in Gadchiroli, Maharashtra. I salute all the brave personnel," Modi tweeted.
"Their sacrifices will never be forgotten. My thoughts & solidarity are with the bereaved families. The perpetrators of such violence will not be spared," he added.