President Vladimir Putin on Sunday thanked Russia's special forces, singling out those who are "heroically fulfilling their military duty" in Ukraine, in a televised address that was also published on the Kremlin website, Reuters reported.
Ukrainian forces were holding off Russian troops advancing on the capital Kyiv, President Volodymyr Zelenskiy said as the biggest assault on a European state since World War Two entered a fourth day.
But the night was brutal, with shelling of civilian infrastructure and targets including ambulances, Zelenskiy said.
Casualties from the war are unclear. A United Nations agency reported 64 civilian deaths and Ukraine claimed to have killed 3,500 Russian soldiers.
More than 100,000 refugees, mainly women and children, have poured into neighboring countries, clogging railways, roads and borders since Russian President Vladimir Putin launched what he called a special military operation on Thursday.
Ignoring weeks of frantic diplomacy and sanctions threats by Western nations seeking to avoid war, Putin has justified the invasion saying "neo-Nazis" rule Ukraine and threaten Russia's security - a charge Kyiv and Western governments say is baseless propaganda.
Offering a glimmer of hope for talks, the Kremlin sent a diplomatic delegation to neighboring Belarus. Ukraine quickly rejected the offer, saying Belarus had been complicit in the invasion.
However, Zelenskiy left the door open for "real negotiations," elsewhere, an adviser said.
Russian missiles found their mark overnight, including a strike that set an oil terminal ablaze in Vasylkiv, southwest of Kyiv, the town's mayor said. Blasts sent huge flames and billowing black smoke into the night sky, online posts showed.
"The enemy wants to destroy everything," said the mayor, Natalia Balasinovich.