Ukrainian President Volodymyr Zelenskyy has a message for Russian troops: Surrender.

"I know that you want to survive," Zelenskyy said during an address Tuesday. "We hear your conversations in the intercepts, we hear what you really think about this senseless war, about this disgrace and about your state."

    That is why Russian soldiers should consider surrendering, he said. "If you surrender to our forces, we will treat you the way people are supposed to be treated. As people, decently. In a way you were not treated in your army. And in a way your army does not treat ours," Zelenskyy said. "Choose!"

Russia's attack on Ukraine is well into its third week. Some Russian soldiers have, in effect, relinquished their weapons and equipment, leaving them for Ukrainian forces, Zelenskyy said.

"The enemy is confused. They did not expect such resistance," Zelenskyy said. "They flee the battlefield. They abandon equipment. We take trophies and use them to protect Ukraine. Today, Russian troops are in fact one of the suppliers of our army."

    Analysts say the steadfastness of Ukraine's defense has surprised Russian President Vladimir Putin. Ukraine forces have had success, having slowed or stalled the Russian advance.While the Russian attack has led to many civilian casualties – more than 1,300 died in the siege of Mariupol alone – an estimated 1,300 Ukrainian troops have been killed, Zelenskyy said. In comparison, he claims 12,000 Russian forces have been killed.

    CBS News reported a U.S. estimate of 5,000 and 6,000 Russian troops killed in the first two weeks of the invasion.

    Russian soldiers may not have known the invasion plans and are not necessarily on board with the Kremlin's mission in Ukraine, The New Yorker reported. That could be why some have abandoned their tanks or vehicles.

    The country's military had downed hundreds of Russian helicopters, tanks, as well as 80 warplanes, "and thousands of other units of equipment," Zelenskyy said.

Eventually, Russia will have to answer for potential war crimes, he said. "Responsibility for war crimes of the Russian military is inevitable. Responsibility for a deliberate humanitarian catastrophe in Ukrainian cities is inevitable," Zelenskyy said. "The whole world sees what is happening in Mariupol. Kharkiv. Chernihiv. Sumy. Okhtyrka. Hostomel. Irpin. In all our cities."