Indian security forces, acting on intelligence, raided a Maoist rebel hideout in the forests of the eastern Chhattisgarh state on Saturday, triggering a gunbattle that killed five paramilitary troops and one rebel, the state's police said. Senior police officer D.M. Awasthi said hundreds of police and paramilitary soldiers took part in the raid after receiving intelligence that a large number of rebels were gathered in Bijapur district. He said at least 12 security personnel were injured in the four-hour firefight, and authorities were working to evacuate the wounded to hospitals. Awasthi said the body of one female rebel was also recovered. Also read: 17 Indian policemen killed in attack by Maoist rebels The rebels used automatic weapons and grenades during the gunbattle, according to Hemant Kumar Sahu, a paramilitary officer, who spoke with The Associated Press by phone. State-run All India Radio tweeted that at least 20 security personnel were missing after the engagement. Also read: Maoist rebels kill 15 police commandos, driver in west India 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. The government has called the rebels India's biggest internal security threat. Last month, a roadside bomb killed at least four Indian policemen and wounded 14 in Narayanpur district of Chhattisgarh state as they were returning from an anti-Maoist operation. Also read: Indian Maoist rebels kill 5 days before national election The rebels, also known as Naxalites, have ambushed police, destroyed government offices and abducted officials. They've also blown up train tracks, attacked prisons to free their comrades and stolen weapons from police and paramilitary warehouses to arm themselves.