Maoist rebels on Saturday ambushed a paramilitary patrol in India's eastern Chhattisgarh state, killing 11 policemen, regional police said.

The attack on the Central Reserve Police Force (CRPF) personnel took place in the forested area of Sukma district, a known area of Maoist activity, about 400 kms from the state capital, Raipur.

"Around 100 CRPF personnel had gone to provide security to ongoing road construction work when the Maoists ambushed them," Inspector General of Police Sunder Raj P. told Reuters.

Four policemen sustained injuries in the attack, he said.

Indian Prime Minister Narendra Modi and Home Minister Rajnath Singh condemned the attack in separate statements on Twitter. Modi said in his statement that Singh would be in Sukma to assess the situation.

In 2010, Maoist fighters ambushed and killed at least 75 police by setting off explosives and firing from hilltops around dense forest in Chhattisgarh, in one of the worst attacks by the insurgents in years.

India then launched its largest-ever security operation, involving tens of thousands of federal troops and policemen, following the attack.

Maoist rebels accuse the Indian government of plundering the mineral rich and underdeveloped east and central regions of the country at the expenses of the poor and landless among whom they draw support.

The level of Maoist violence, however, has fallen in recent years.