Ukrainian forces reportedly advanced on Russian positions near Kharkiv and Kherson, making small territorial gains amid an ongoing Russian offensive in the eastern Donbas region.

The May 7 claims by Oleskiy Arestovych, a top adviser to Ukrainian President Volodymyr Zelenskiy, come just two days before Russia holds major ceremonies to mark Victory Day, the anniversary of the defeat of Nazi Germany.

Russian President Vladimir Putin’s speech on May 9 will be closely watched to see if he will announce a general mobilization or some other major strategic shift, in a bid to turn the tide of the war, now in its 73rd day.

In the early weeks after the February 24 invasion, Russian forces were thwarted in their attempts to seize Kyiv and other Ukrainian cities, suffering heavy losses of personnel and equipment. Commanders then later withdrew units from areas near Kyiv and repositioned to the Donbas.

Russia’s last official tally of its military casualties was 1,351. Western officials, however, say the toll is at least 15,000, and Ukrainian officials claim the tally exceeds 20,000. Zelenskiy said last month that between 2,500 to 3,000 Ukrainian troops have been killed, though that figure is believed to be an undercount.

Russia’s Defense Ministry said on May 6 that its forces were continuing to advance on positions in the Donbas, and had destroyed an ammunition depot in Kramatorsk and shot down two Ukrainian warplanes.