Ukraine’s general staff said the Russians were pulling back from the northeastern city of Kharkiv and focusing on guarding supply routes, while launching mortar, artillery and airstrikes in the eastern Donetsk province in order to “deplete Ukrainian forces and destroy fortifications.”

Defense Minister Oleksii Reznikov said Ukraine was “entering a new – long-term – phase of the war.”

As the country’s top prosecutor put a Russian soldier on trial for war crimes, the first of dozens that could face charges, President Volodymyr Zelenskyy said Ukrainians were doing their “maximum” to drive out the invaders and that the outcome of the war would depend on support from Europe and other allies.

“No one today can predict how long this war will last,” Zelenskyy said in his nightly video address late Friday.