Three months after invading Ukraine, Russian forces are trying to encircle Ukrainian troops in twin cities straddling the Siverskyi Donets River in eastern Ukraine. Motuzyanyk said Russian forces had not given up attempts to cross the river.

"Now we are observing the most active phase of the full-scale aggression which Russia unfolded against our country," he told a televised briefing.

"The situation on the (eastern) front is extremely difficult, because the fate of this country is perhaps being decided (there) right now."

(Reporting by Max Hunder, Editing by Timothy Heritage)