Terrorists belonging to banned groups United National Liberation Front (UNLF) and People's Liberation Army (PLA) were allegedly part of the mob from which gunshots were fired at an army officer that left him severely injured in Manipur, officials said Monday.

Central security agencies have now warned about the possibility of terrorists mingling with crowds during any protest to stoke tensions in the restive Manipur state, they said.

The warning has come after a Lt Colonel of the army was injured last week during a standoff with a group of people, including Meira Paibis (women vigilantes), who attempted to attack tribals at Molnoi village near Pallel in Tengnoupal district but were stopped by the army and Assam Rifles.

During the stand-off, a bullet hit Lt Col Raman Tyagi in his hand, an incident that led to a crackdown on the protesters who were determined to march towards the tribal village.

Lt Col Tyagi had to be airlifted from Manipur to Guwahati where he underwent surgery, the officials said. He was earlier evacuated to a military hospital in Leimakhong by a helicopter, after which he was shifted to neighbouring Assam for specialised treatment.

The investigation into the incident led the security agencies to conclude that the terrorists of the banned groups were part of the crowd, they said.

The officials said they had been warning for the past few weeks about the resurgence of near dormant banned groups like UNLF, PLA, Kanglei Yawol Kanba Lup (KYKL) and People's Revolutionary Party of Kangleipak (PREPAK) in the state.

They said that at present UNLF had a cadre strength of 330 followed by PLA with 300 and KYKL with 25 who were active within the groups of the majority community.

The overwhelming support being extended to cadres of these banned organisations was witnessed on June 24, when Army and Assam Rifles, based on specific intelligence, nabbed 12 members of KYKL in East Imphal including self-styled 'Lt Colonel' Moirangthem Tamba alias Uttam.

Uttam was one of the masterminds of the ambush on 6 Dogra regiment in 2015 that left 18 army soldiers dead.

The UNLF has in the past been largely involved in extortion targeting contractors and businessmen.

The PLA, which initially took shape under the name of 'Polei', the ancient name of Manipur, had an aim to liberate Manipur and establish an independent Meitei land in Imphal Valley.

The KYKL, which runs on extortion and openly supports other terror groups, is considered a mercenary group with no ideology and cadres mainly drawn from criminals and drug addicts.

The PREPAK, which has been banned by the government for its secessionist ideology of so-called liberation of Manipur and whose funding mainly comes from extortion of businessmen especially pharmacies, indulged mainly in drug trafficking and smuggling.

This terror group is also involved in extortion on behalf of PLA and UNLF and passes the amount after retaining a share.

The officials said that there were apprehensions that the arms and ammunition looted from the Manipur police armoury could have landed with these terror groups.

Among the arms looted included .303 rifles, Medium Machine Guns (MMG) and AK assault rifles, carbines, Insas Light Machine Guns (LMG), Insas rifles, M-16 and MP5 rifles.

Besides these, around 6 lakh bullets have been found missing during the waves of attacks carried out on police and other security officials from May 3 when the ethnic clashes began in the state with two dominant communities targeting each other. These attacks have so far claimed over 160 lives.

The officials said around 4,537 arms and 6.32 lakh rounds of ammunition were missing mainly from Manipur Police Training Centre (MTPC) at Pangei in East Imphal, 7th India Reserve battalion and 8th Manipur Rifles, both located at Khabeisoi in Imphal city.

According to the officials, out of the stolen weapons, 2,900 fell in the lethal category whereas others comprised teargas and mini flare guns.

The looted arms and ammunition were mainly with the rioters in the valley, while those in the hills had only 5.31 per cent of such weapons, they said.