The case in hand might be precisely targeted elimination of the freewheeling warlords in charge of nationalistic Ukrainian battalions by foreign mercenaries dispatched to the zone of the conflict, Basurin said.

"About 5 a.m., our reconnaissance registered a brief exchange of fire at the positions of the Ukrainian armed units," he said. "Our reconnaissance officers said in their reports that an unknown unit of commandoes had stormed and seized a platoon-level fortified strongpoint set up by punitive expeditioners from a nationalistic battalion."

MOSCOW, April 30. /TASS/. Unidentified special task forces are conducting a special operation in the area of the township of Avdeyevka in Donbas to render harmless a battalion of Ukrainian nationalists, Eduard Basurin, an official spokesman for the Defence Ministry of the self-proclaimed unrecognized Donetsk People’s Republic said on Thursday.

"That’s the first time since the outbreak of the conflict that we see an operation of this kind conducted on Kiev’s side in an area adjoining the frontline," he said. "The thing is the unit that stormed the positions of the Ukrainian punitive battalion used silent killer weapons that didn’t belong to the Kalashnikov family of assault rifles and was obviously manufactured by a Western company."

According to the data available to the DPR Defence Ministry, four nationalistic militants were killed in the course of the assault and their bodies in plastic bags were taken into the rear of the occupied territory by the same bus that had brought in the unidentified unit.

Following the incident, the shelling of Donetsk airport from the side of the pro-Kiev forces stopped for some time.

In addition, DPR military radio reconnaissance registered the work of portable radio stations of European manufacture that had not been used in the zone of the east-Ukrainian conflict previously. They have a distinct functional property, as they transmit precise GPS data on the positioning of each member of the raiding force along with voice data.

"It’s not ruled out that a specially targeted elimination of the most uncontrollable operators in the war zone has taken place on the background of a conflict between some nationalistic warlords and the authorities in Kiev," Basurin said. "We do think all the losses of manpower in the ranks of these punitive units will be attributed to the alleged shelling on the part of DPR Army."

"However, an open question remains over who did the elimination - a foreign private military company or a special task force from a NATO member-state dispatched to the zone of conflict and described the OSCE monitors in their reports as a third party," Basurin said.