Suspected Maoist rebels set off a land mine and opened fire Saturday on a convoy of cars carrying local leaders and supporters of India’s ruling Congress party in eastern India, killing at least 17 people and wounding 24 others, police said.

Senior police officer M. Gupta said the attack occurred in the Sukma area, about 215 miles south of Raipur, the capital of Chhattisgarh state.

Two state party leaders and five police officers were among those killed in the attack, state police said, while other victims were party supporters.

“We are devastated,” said the Congress party’s president, Sonia Gandhi, who denounced what she called a “dastardly attack” on India’s democratic values.

Police identified one of those killed as Mahendra Karma, a Congress leader in Chhattisgarh state who founded a local militia, the Salwa Judum, to combat the Maoist rebels after they were accused of atrocities against tribals — indigenous people at the bottom of India’s rigid social ladder.

Among the wounded Congress party members was 83-year-old Vidya Charan Shukla, a former federal minister, police said, adding that the suspected rebels also took away a local party leader, Nand Kumar Patel, and his son.

The Congress party is the main opposition party in the state.

The rebels, known as Naxalites, have been fighting the central government for more than four decades, demanding land and jobs for tenant farmers and the poor. Prime Minister Manmohan Singh has called them India’s biggest internal security threat.