Indian police say Maoist rebels have killed 10 policemen in a landmine attack in the central state of Chhattisgarh.

The officer in charge of Maoist operations, Ram Niwas, told reporters the Maoists targeted a police vehicle and triggered a massive explosion, 400 kilometers from the state capital of Raipur. Three other officers were wounded in the blast.

On Thursday in Chhattisgarh, police said five policemen were killed in a shootout when rebels attacked a police camp in the Naryanpur district. There were no reports of casualties among the attackers.

Indian leaders call the 40-year Maoist insurgency the country's biggest internal security threat.

The rebels have infiltrated more than 20 Indian states, saying they are fighting for jobs and land for the poor.

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