Indian officials say Maoist rebels killed at least 26 police, including a senior officer, in two separate attacks Sunday.

Officials said the attacks occurred in the Rajnandangaon district of the central state of Chhattisgarh, but they did not provide any other details.

Security forces have launched an operation in the area to find the attackers.

Last month, Indian security forces captured a key Maoist stronghold in West Bengal state after battling through landmines and gunfire with the rebels.

The Maoist rebels are part of a wider group of insurgents known as Naxalites who say they fight for the rights of the poor. Indian authorities accuse the rebels of killing at least five members of the region's ruling communist party, Communist Party of India-Marxist.

India's central government has labeled the faction a terrorist organization.

The Maoists are active in at least 13 of India's 29 states.  Their violent insurgency has killed thousands of people in the past few decades.
 
Indian Prime Minister Manmohan Singh has called the Maoists the gravest threat to India's internal security.

Some information for this report was provided by AFP, AP and Reuters.