PATNA, India — Maoist rebels blew up a bus on Thursday, killing four civilians and a paramilitary soldier, in a central Indian state where legislative elections are to be held next week.

Senior police officer D.M. Awasthi said the attack occurred in Dantewada district of Chhattisgarh state, a stronghold of the insurgents.

Two other soldiers were wounded in the attack and were hospitalized, Awasthi said.

The New Delhi Television channel said an explosive device tore through the bus, which was carrying civilians and paramilitary soldiers.

The rebels have put up posters in the area warning people against voting in the elections.

It was the third Maoist attack in the state in less than two weeks. In the previous two attacks, four paramilitary soldiers, two policemen and one television cameraman were killed.

The Maoist rebels, inspired by Chinese revolutionary leader Mao Zedong, have been fighting the Indian government for more than four decades, demanding land and jobs for tenant farmers, the poor and indigenous communities. They have thousands of fighters and control vast swaths of territory in several Indian states.

The government has called the rebels India's biggest internal security threat.

The rebels, also known as Naxalites, have ambushed police, destroyed government offices and abducted officials. They have blown up train tracks, attacked prisons to free their comrades and stolen weapons from police and paramilitary warehouses.