Ukraine's military command said Thursday that government forces had killed "around 50 Russian occupiers" while repulsing an attack on a town on the frontline with Moscow-backed rebels.
AFP could not immediately confirm the death toll.
"Shchastya is under control. 50 Russian occupiers were killed. Another Russian plane was destroyed in the Kramatorsk district. This is the sixth," the armed forces general staff said on Twitter.
Ukraine's border guard service said that three of its servicemen had been killed in the southern Kherson region and that several more were wounded.