The three persons killed in an exchange of fire between security forces and Naxals who were part of a violent mob of villagers near a police camp in Chhattisgarh's Sukma district on May 17 have been identified as members of the front outfits for the CPI (Maoist), as per the preliminary probe by the police.

The incident occurred on Monday afternoon when a large number of villagers was protesting against the newly set up camp near Silger, a Maoist stronghold located along the border of Sukma and Bijapur districts.

Human rights activists on Tuesday demanded a high-level probe after three people were killed in an exchange of fire between security forces and alleged Naxals near a new police camp in Chhattisgarh's Sukma district a day earlier.

While villagers claimed security forces opened fire unilaterally on Monday, police said Naxals were part of the crowd that was protesting against the opening of the Silger camp and these ultras started the gun-battle.

According to police, three persons were killed and five others injured in the incident.

Local villagers had claimed the deceased and the injured persons were villagers and not Naxals.

"The preliminary investigation revealed the three deceased were allegedly linked with front organisations of the banned CPI (Maoist) and police are trying to further ascertain this input," Inspector General of Police (Bastar range) Sundarraj P said on Wednesday.

Prima facie, the deceased were identified as Uska Pandu, a Bhumkal commander from Timmapur village (Sukma), Kowasi Waga, DAKMS (Dandakaranya Adivasi Kisan Majdoor Sangthan) member from Chhutwahi and Kursam bhima, Militia member from Gundem village (Bijapur), the IGP said.

All these formations are front outfits for Maoists that function at the village level, he added.

The bodies have been handed over to their relatives, the police officer added.

Of the five persons who were injured in the incident, four are found to be the members of the front outfits for the Maoists, the IGP added.

The camp, where personnel from CRPF's 153rd and 168th battalions, CRPF's elite unit CoBRA, Special Task Force (STF) and District Reserve Guard (DRG) are stationed, was opened on May 12.

Since May 14, residents from nearby villagers had been protesting demanding removal of the camp.

Explaining the sequence of events, the IGP said the protesting villagers had left the spot on Sunday night after pacified by police officials and an executive magistrate but Maoists sent them back forcibly near the camp on Monday.

Around 3,000 villagers armed with bows and arrows, axes, sharp weapons, sticks and stones charged towards the camp shouting slogans for removal of the camp on Monday afternoon.

The mob hurled stones at security personnel positioned at the outer cordon, leaving many of them injured and causing damage to two Mine Protected Vehicles (MPVs) parked there, Sundarraj said.

The crowd also tried to dismantle barricading around the camp and snatched rifles and magazines from security personnel, he said.

"Meanwhile, ultras belonging to Jagargunda, Pamed and Kerlapal area committees of Maoists and other lower-rung cadres who were hiding in the crowd opened fire at security personnel. Despite warnings, they continued firing that triggered a stampede like situation," the officer said, adding the security forces retaliated in self-defence.

After the situation normalised, the bodies of three persons were recovered.

The injured persons were later admitted to a hospital, he said.

Villagers had alleged that police lathi-charged them and fired unilaterally, a claim denied by the police.

Alok Shukla, the convener of Chhattisgarh Bachao Andolan (CBA), a group of activists, on Tuesday alleged that police opened fire on tribals who were protesting against the camp.

He demanded that the incident be probed by a retired judge of the High Court in a time-bound manner and an FIR be registered against the guilty.