Ukrainian President Volodymyr Zelenskyy warned his nation on Sunday night that the coming week would be as crucial as any in the war, adding he expects Russian troops to "move to even larger operations in the east of our state", The Associated Press reported. In his nightly video address, Zelenskyy accused Russia of trying to evade responsibility for war crimes. "The day will come when they will have to admit everything. Accept the truth," he said. "When people lack the courage to admit their mistakes, apologize, 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," said the Ukrainian President. Russia's military is believed to be preparing for a large, focused push to expand control in Ukraine’s east. Russia-backed separatists have fought Ukrainian forces in the eastern Donbas region since 2014 and declared some territory there as independent. Britain's Defense Ministry reported Sunday that Russian forces were trying to compensate for mounting casualties by recalling veterans discharged in the past decade. On Sunday, Russian forces shelled government-controlled Kharkiv and sent reinforcements toward Izyum to the southeast in a bid to break Ukraine's defenses, the Ukrainian military command said. Meanwhile, Ukraine's prosecutor general on Sunday said her team has documented 5,600 cases of war crimes perpetrated by the Russian government and its leading figures since the invasion began February 24. Speaking to British broadcaster Sky News , Iryna Venediktova said Ukraine has identified 500 suspects, including "top" Russian military personnel, politicians and "propaganda agents." On Saturday, British military intelligence accused Russian troops of continuing to employ improvised explosive devices (IEDs) to inflict large-scale civilian and military casualties in Ukraine. "Russian forces also continue to attack infrastructure targets with a high risk of collateral harm to civilians," the Ministry said, adding that Russia's pullback from parts of northern Ukraine leaves evidence of the disproportionate targeting of non-combatants. On Friday, a rocket attack on a train station in the eastern Ukrainian city of Kramatorsk left at least 50 dead . Photos of the carnage showed bodies covered with sheets lining the ground and the exploded shell of a rocket that had the words “For the children” painted on it in Russian, The Associated Press reported. US President Joe Biden later accused Russia of carrying out a "horrific atrocity" Friday’s incident came days after the discovery of hundreds of bodies in the Kyiv suburb of Bucha as Ukrainian forces retook areas previously occupied by the Russian army. Germany, France, Britain, the US, and the European Union condemned Russia following the discoveries, with France, Britain, and Germany calling for a war crimes investigation. On Thursday, the UN General Assembly voted in favor of suspending Russia from the UN Human Rights Council in wake of its actions in Ukraine. Related articles: Why Trump's Ukraine policies have US Jews worried Trump Admin. has set date for full ceasefire in Ukraine One dead in Ukrainian attack on Moscow Is Russia planning to attack another European country?