As many as 12 Naxalites were killed in a fierce encounter with security forces in Chhattisgarh's Bijapur district on Thursday, a senior police official said.

The gunfight broke out at around 9 am in a forest of south Bijapur when a joint team of security personnel was out an anti-Naxalite operation and the intermittent exchange of fire lasted till late in the evening, he said.

Personnel belonging to the state police's District Reserve Guard (DRG) from three districts, five battalions of CoBRA (Commando Battalion for Resolute Action - an elite jungle warfare unit of the CRPF) and the 229th battalion of CRPF were involved in the operation, he said.

"As per preliminary information, 12 Naxalites were killed in the gunfight. Further details were awaited as a search operation was still underway in the area," the official informed.

No harm was reported to security forces, he said.

With this, 26 Naxalites have been gunned down in separate encounters in the state so far this month.

On January 12, five Maoists, including two women, were killed in an encounter with security personnel in the Madded police station area of Bijapur district.

Last year, 219 Naxalites were neutralised by security forces in separate encounters in the state.