NEW DELHI (AP) — Police in India killed at least 29 suspected Maoist rebels in the central state of Chhattisgarh on Tuesday, authorities said, three days ahead of the start of a national election in which Prime Minister Narendra Modi is seeking a third term.

According to a statement, police launched a raid after a tipoff about the presence of Maoists in the Kanker district. Three members of the security forces were wounded in the gunfight, after which police seized several weapons.

Indian soldiers have been battling Maoist rebels across several central and northern states since 1967, when the militants — also known as Naxalites — began fighting to demand more jobs, land and wealth from natural resources for the country’s poor indigenous communities.

Indian government says the insurgents, inspired by Chinese revolutionary leader Mao Zedong, pose the country’s most serious internal security threat.