Russia's Defense Ministry announced that 63 Russian soldiers were killed on Monday in a Ukrainian New Year's Eve attack on their quarters in the Russian-controlled part of Ukraine's Donetsk province.
Footage posted online showed a building purported to be a vocational college in Makiivka, the regional capital of Donetsk's twin city, reduced to a field of smouldering rubble.
Earlier, the Ukrainian defence ministry claimed that up to 400 Russians had been killed.
Daniil Bezsonov, a senior Russian-backed regional official in Moscow-controlled parts of the Donetsk region, said the vocational college was hit by US-made HIMARS rockets around midnight, just as people in the region were celebrating the start of the New Year.
According to Rybar, a Russian pro-war military blogger with over one million Telegram subscribers, more than 100 people were injured in the strike and rubble was still being cleared.
Rybar stated that there were approximately 600 people in the building and that ammunition was stored in the same location.
Only in the final paragraph of a 528-word daily battlefield roundup did Russia's Defence Ministry provide an estimate of the death toll.
Reuters was unable to verify the battlefield accounts but confirmed the location of the video based on the nearby buildings and road layout seen in the footage, though not the date.
According to a source close to the Russian-installed Donetsk leadership, the building housed some of the 300,000 or more soldiers mobilised since September, many of whom have already been sent to the front to bolster Russia's faltering military campaign in Ukraine.
Igor Girkin, a nationalist and former Federal Security Service (FSB) officer who helped Russia annex Crimea in 2014 and then organise pro-Russian militias in eastern Ukraine, said in a Telegram post on Monday that “the number of dead and wounded runs into many hundreds.”
Girkin, who has bitterly criticised Russia's military failures in Ukraine, also said ammunition had been stored at the facility.
“This is not the only such (extremely dense) deployment of personnel and equipment in the destruction zone of HIMARS missiles,” he wrote. And – yes – this is not the first such case, he added.
Archangel Spetznaz Z, another Russian military blogger wrote on Telegram, “Who came up with the idea to place personnel in large numbers in one building, where even a fool understands that even if they hit with artillery, there will be many wounded or dead?”