Maoists have developed a "pen gun", security forces in Chhattisgarh said.

An encounter with Maoists in Chhattisgarh this week ended with a stunning find by security forces. In the cache of arms and ammunition - found after the fierce gunfight that left eight Maoists including four women dead - was what most accurately can be described as a "pen gun". The police suspect the gun was developed by the technical team of the Maoists.

The contraption was found when a joint team of the District Reserve Guard and the Special Task Force were conducting searches in the Timinar and Pusnar villages along the border of Bijapur and Dantewada districts after the encounter on Thursday. Two Insas and two .303 rifles each and a 12-bore shotgun were also recovered.

"We recovered seven firearms including one pen gun developed by the local technical team of Naxalites. They use 9 mm bullets in this pen gun and was made by using small pipe, pin as trigger," Dantewada SP Kamalochan Kashyap said.

The pen gun has a range of 9 to 10 metres and the self-styled female Maoist commander Jaini fired two bullets using it during the encounter when she dropped her Insas rifle after getting injured in the encounter, police sources said. Jaini was the Bhairamgadh Area commander.

According to sources, small action teams of Maoists have taken to using pen guns which can be carried discreetly and are also used by their cadres in emergency situations when they lose their main weapons.

The encounter on Thursday began when security forces launched a search operation along the border of Bijapur and Dantewada districts, around 450 km from the state capital Raipur, following a tip-off. All eight Maoists, including four women, were killed in the gunfight that went on for two hours.