Ukraine's president warned his nation on Sunday night that the coming week would be as crucial as any in the war.
"Russian troops will move to even larger operations in the east of our state," Volodymyr Zelenskyy said in his nightly address.
He accused Russia of trying to evade responsibility for war crimes.
"When people lack the courage to admit their mistakes, apologise, adapt to reality and learn, they turn into monsters. And when the world ignores it, the monsters decide that it is the world that has to adapt to them. Ukraine will stop all this," Zelenskyy said.
"The day will come when they will have to admit everything. Accept the truth," he said.
He again called on Western countries, including Germany, to provide more assistance to Ukraine. During talks with German Chancellor Olaf Scholz, Zelenskyy said he discussed "how to strengthen sanctions against Russia and how to force Russia to seek peace".
"I am glad to note that the German position has recently changed in favor of Ukraine. I consider it absolutely logical," Zelenskyy said.
Meanwhile, the president of the European Commission said the questionnaire she handed Zelenskyy during her visit to Kyiv represents a very important step forward.
Ursula von der Leyen said Sunday on CNN's State of the Union that Ukraine's response will enable her to decide whether to recommend the nation as a candidate to join the European Union.
The process normally takes years, but she has said Ukraine's application could take just weeks to consider. She said Ukrainians "belong to our European family, without any question."
"Yesterday, somebody told me: 'You know, when our soldiers are dying, I want them to know that their children will be free be and be part of the European Union'," von der Leyen said. "They are in an extraordinary situation, where we have to take unusual steps."
"One thing is clear for me: After this war, when Ukraine will be rebuilt, when we support Ukraine in reconstructing this country, this will be accompanied by reforms. So, it is an extraordinary way to shape the country and to go down the path towards the European Union."