Three CRPF personnel were killed in a Maoist attack in Odisha's Nuapada district on Tuesday, police said.

The incident happened in Patadhara Reserve Forest in Bheden block when the CRPF personnel were going from one camp to another, they said.

"Unfortunately, three jawans have attended martyrdom in Nuapada. Our senior officers are on the way to the site," Odisha's Director-General of Police SK Bansal told PTI.

It is suspected that the Maoists had prior information regarding the movement of the forces, another police officer said.

All of a sudden, they opened fire on the forces, he said.

According to a preliminary report, seven jawans were on the move when the incident took place, he added.

The deceased include a constable and two assistant sub-inspector-rank personnel of the Central Reserve Police Force (CRPF), officials said.

Combing operations have been intensified in the area, and more teams of the Special Operations Group (SOG) and CRPF are moving to the site, they said.

The operations would continue till the Maoists are flushed out, the DGP said, expressing deep condolences to the bereaved families.

The supreme sacrifice of the personnel would not go in vain, he said.