A Ukrainian strike on a training ground in Moscow-occupied Donetsk has killed at least 60 Russian troops, the BBC's Russian Service quoted sources as saying.
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Russian soldiers from the 36th Guards Motorized Rifle Brigade had been lined up and were waiting for the arrival of Major General Oleg Moiseyev, the commander of the 29th Russian Army, when the strike occurred on February 20, the report said.
Ukraine has not commented on the report.
Pro-Russian social media outlets posted videos and photos purportedly showing dozens of uniformed dead bodies, accusing Moiseyev of making soldiers stand in line waiting for his arrival when they were hit.
Meanwhile, three civilians were killed and 13 others were wounded by Russian shelling of three eastern Ukrainian regions, local authorities reported on February 21.
One person was killed in Kramatorsk, in the Donetsk region, while eight others were wounded, regional Governor Vadym Filashkin said.
In the Kharkiv region, two farmers were instantly killed when their car was struck in the village of Petropavlivka in the Kupyansk district, while one woman was wounded, regional Governor Oleh Synyehubov said.
In the Kherson region, four people were wounded in Russian shelling, mortar, and drone strikes, local authorities reported.
Air-defense forces shot down 13 out of 19 drones launched by Russia at four Ukrainian regions early on February 21, Ukraine's Air Force reported, adding that one S-300 missile and four Kh-22 cruise missiles were also destroyed.
The drones were downed in the Kharkiv, Dnipropetrovsk, Zaporizhzhya and Donetsk regions, the air force said.
It said that some of the remaining six drones did not reach their targets.
The four Kh-22 cruise missiles were shot down in the central Poltava region.