At least 60 Russian troops have been killed after a training area in occupied eastern Ukraine was hit by two missiles.
Sources familiar with the situation said that troops had gathered at the site in Donetsk region for the arrival of a senior commander.
Video footage of the incident appeared to show large numbers of dead, BBC reported.
A Russian official confirmed that a strike took place but described the reports as "grossly exaggerated".
The attack reportedly came hours before Russian President Vladimir Putin met his Defence Minister Sergei Shoigu.
Reports say members of the 36th motorised rifle brigade, normally based in the Transbaikal region of Siberia, were waiting for the arrival of Maj-Gen Oleg Moiseyev, commander of the 29th Army of the Eastern military region, at a training area near the village of Trudovske.
A soldier who survived the incident said during a video recording of the aftermath that the brigade's commanders had made them stand in an open field.
They were reportedly hit by two missiles fired from the US-made HIMARS launch system.
This and other videos and stills show dozens of soldiers apparently lying dead in a field.
bd-pratidin/GR
