Russian President Vladimir Putin's "special military operation" into neighboring Ukraine began on Feb. 24, with Russian forces invading from Belarus, to the north, and Russia, to the east. Ukrainian troops have offered "stiff resistance," according to U.S. officials.
The Russian military has since launched a full-scale ground offensive in eastern Ukraine's disputed Donbas region, capturing the strategic port city of Mariupol and securing a coastal corridor to the Moscow-annexed Crimean Peninsula.
A look at the two leaders at the center of the war in Ukraine and how they both rose to power, the difference in their leadership and what led to this moment in history.
Here's how the news is developing. All times Eastern.
Apr 19, 2022, 6:14 AM EDT
Ukraine says Russia is stepping up attacks in the east
Ukrainian military spokesperson Oleksandr Shtupun said Tuesday that Russian forces are stepping up attacks in the east.
Russian forces are currently focused on breaking through Ukrainian defences in the eastern Donetsk and Luhansk oblasts, as well as establishing full control over the strategic port city of Mariupol, according to Shtupun.
Servicemen of the Donetsk People's Republic militia look at bodies of Ukrainian soldiers placed in plastic bags in a tunnel, part of the Illich Iron & Steel Works Metallurgical Plant, the second largest metallurgical enterprise in Ukraine, in an area controlled by Russian-backed separatist forces in Mariupol, Ukraine, April 18, 2022.
Alexei Alexandrov/AP
In the south, Russian forces are focused on reaching the administrative border of the Kherson Oblast while continuing to shell the city of Mykolaiv, Shtupun said.
Meanwhile, Belarus continues to provide its territory to Russia for reconnaissance and launching air strikes against Ukraine. The Ukrainian cities of Kharkiv, Dnipro, Mykolaiv and Kherson were all shelled overnight, according to Shtupun.
-ABC News' Yulia Drozd
Apr 19, 2022, 5:33 AM EDT
Russian military calls on Ukrainian troops in Mariupol to surrender
The Russian military is calling on Ukrainian troops in besieged Mariupol to surrender by midday on Tuesday.
Russian forces have been trying to seize the strategic port city in eastern Ukraine's war-torn Donetsk Oblast since the start of the invasion on Feb. 24. The Russian Ministry of Defense said it is ready to declare a temporary ceasefire in Mariupol on Tuesday from 1:30 p.m. local time.
Ukrainian troops holed up on the grounds of the Azovstal iron and steelworks plant in Mariupol have until 12 p.m. local time to stop all fighting and lay down their arms, according to Col. Gen. Mikhail Mizintsev, head of Russia's National Defense Control Center. Moscow has proposed this plan "given the catastrophic situation in the Azovstal Iron and Steel Works, as well as for purely humanitarian considerations," Mizintsev told Russian state media on Tuesday.
A satellite image shows an overview of Azovstal Iron and Steel Works in Mariupol, Ukraine, April 9, 2022.
Maxar Technologies via Reuters, FILE
"All those who will lay down arms are guaranteed that their lives will be spared," he added. "The actual start of the temporary ceasefire shall be marked by both sides by raising flags -- red flags by the Russian side and white flags by the Ukrainian side along the entire perimeter of Azovstal. Furthermore, their readiness to put the temporary ceasefire into effect shall be confirmed by the sides via all communication channels."
According to Mizintsev, "absolutely all" Ukrainian troops and foreign mercenaries will be allowed to leave the plant without any weapons or ammunition from 2 p.m. to 4 p.m. local time. Moscow guarantees to each Ukrainian soldier who surrenders that their life will be spared and their rights as prisoners of war will be respected, Mizintsev said.
Apr 18, 2022, 7:55 PM EDT
Zelenskyy: Russian forces have begun offensive in Donbas region
Ukrainian President Volodymyr Zelenskyy said Russian forces have begun their offensive in the eastern part of the country after a week of building up troops.
"It can now be stated that Russian troops have begun the battle for Donbas, for which they have been preparing for a long time," the president said in his nightly address. "A very large part of the entire Russian army is now focused on this offensive."
Ukrainian and U.S. officials have said Russian troops exiting the Kyiv region over the last week were moving to eastern Ukraine as part of a new effort to take over land partially controlled by the self-proclaimed Republics of Donetsk and Luhansk. Those two breakaway regions were already aligned with Russia following a war that began in 2014.
Ukrainian President Volodymyr Zelenskyy speaks during his nightly address, saying that the "Battle of Donbas" has begun, in Kyiv, Ukraine, April 18, 2022.
Ukrainian Presidential Press Service via Reuters
Zelenskyy, however, warned that Russian forces would not be successful in taking all of the land in the southeastern region of Ukraine.
"No matter how many Russian soldiers are driven there, we will fight," he said. "We will defend ourselves. We will do it daily. We will not give up anything Ukrainian, and we do not need what's not ours."
Apr 18, 2022, 4:54 PM EDT
Combat in eastern Ukraine part of Russia's 'shaping operations' for future offensive
Pentagon spokesman John Kirby said Monday that while there has been combat in the Donbas region in eastern Ukraine for some weeks, it is part of Russia’s ongoing "shaping" operations for a future offensive, and not the offensive itself.
"We're not disputing that there's not combat going on in the Donbas," Kirby said. "What we're saying is that we still consider that what we're seeing to be a piece of shaping operations."
“That the Russians are continuing to set conditions for what they believe will be eventual success on the ground by using, by putting, in more forces, putting in more enablers, putting in more command and control capability for operations yet to come," he said.
A woman cries after boarding a bus to leave Severodonetsk, in eastern Ukraine's Donbas region, April 13, 2022.
Ronaldo Schemidt/AFP via Getty Images
Asked to clarify his answer, Kirby replied: "We believe that the Russians are shaping and setting the conditions for future offensive operations. We also see ... that there is active combat going on right now in the Donbas as there has been for the last several weeks."
Kirby described the fighting in the besieged port city of Mariupol as part of that since the Russians are "trying to set the conditions for more aggressive, more overt and larger ground maneuvers in the Donbas."
A Russian military convoy moves on a highway in an area controlled by Russian-backed separatist forces near Mariupol, Ukraine, April 16, 2022.
Alexei Alexandrov/AP
He added that the Russians have also continued to flow in artillery, helicopters, enabling troops and more command and control units as part of the groundwork for that upcoming operation.
Kirby said that the U.S. believes that Russia has reinforced the number of battalion tactical groups in eastern and southern Ukraine as part of their preparations for a large operation in the Donbas region.
