Four CRPF personnel were killed and three others injured after their colleague opened fire at them in a camp of the paramilitary force in Chhattisgarh's Sukma district on Monday, a police official said.

The incident took place at around 3.15 am in the camp of the Central Reserve Police Force's (CRPF) 50th battalion in Linganpalli village under Maraiguda police station of the area of the district, located nearly 400 km from the state capital Raipur, Inspector General of Police (Bastar range) Sundarraj P said.

As per preliminary information, constable Reetesh Ranjan fired at his colleagues with his service weapon, an AK-47 rifle, the official said.

The accused, constable Reetesh Ranjan, was "overpowered" by fellow troopers at Lingalapalli camp in Sukma district of south Bastar region soon after the shootout. As per preliminary information, Ranjan fired at his colleagues with his service weapon, an AK-47 rifle.

The official said that the seven injured personnel were immediately shifted to a hospital in the nearby Bhadrachalam area of neighbouring Telangana, where doctors declared four of them dead on arrival.

He said that those killed were identified as constables Rajmani Kumar Yadav, Rajib Mondal, Dhanji and Dharmendra Kumar, adding that three other injured personnel were being treated at the hospital.

"Prima facie, it seems that due to some emotional stress leading to sudden psychological disbalance, constable Reetesh Ranjan lost his control and in a fit of rage opened fire on his colleagues," a CRPF spokesperson said.

Constable Ranjan was immediately held and his interrogation is underway, the official said.

In a similar incident of fratricide in January this year, a CRPF jawan was killed and another one injured after their colleague opened fire at them in their camp in the state's Bastar district, police earlier said.

The offender had then tried to commit suicide by shooting himself, they said.