A suspected bomb attack by Maoist rebels has 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 said. "More teams have been sent to site for rescue and combat operations," said the officer, who did not want to give his name. 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 12:30 pm [local time]. In another blast, 15 security officers were killed and rescue operations are ongoing to ascertain the damage," Gadchiroli police official Prashant Dute said. The Maoist insurgents, known as Naxals, have battled the state for decades, saying they are fighting for people left out of a long economic boom in Asia’s third-largest economy. Tens of thousands have been killed. 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," Mr 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. In April 2018, raids on rebel camps in the region killed at least 37 insurgents, police said. Many of the slain rebels were women, police said. Wednesday's attack was the deadliest by Maoists in India since 2017 when at least 25 paramilitaries were killed in the Sukma district of central Chhattisgarh state. That in turn was the deadliest since Maoists killed 75 paramilitary soldiers from the Central Reserve Police Force (CRPF) in 2010 in the same state.