Police say suspected Maoist rebels have killed 11 police officers in eastern India.

Friday's attack took place in the Bijapur district of Chhattisgarh state.

Police say security personnel were ambushed by Maoists as they patrolled the area. At least five rebels were killed in the ensuing gunfight.

While Maoist rebels have infiltrated more than 20 Indian states, Chhattisgarh is the center of their decades-long uprising.

The rebels say they are fighting on behalf of landless farmers and tribal members disenchanted with the communist state government's attempts to push industrialization.

Indian leaders call the insurgency the country's biggest internal security threat.

Indian officials say close to 1,200 people were killed in rebel-related violence in 2010. At least 250 people have been killed so far this year.