Ukraine's Anti-Terrorist Operation (ATO) headquarters has reported about a skirmish with a special forces group of the Russian occupation forces in Luhansk region's Popasna district in Donbas, eastern Ukraine."There was a skirmish with a special forces unit of the Russian occupation forces near the village of Novozvanivka from the side of the village of Kalynove," the ATO HQ wrote in an update for the past day on Facebook on Tuesday.