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 21, 2022, 2:20 PM EDT
Most Russian forces focused on Donbas: US
The U.S. has assessed that the Ukrainian port city of Mariupol remains contested, and that Russian airstrike activity remains focused there and on the Donbas region, a senior U.S. defense official said Thursday.
Russia now has 85 battalion tactical groups, each made up of roughly 800 to 1,000 troops, inside of Ukraine, the official said. More of these groups are headed to the Donbas region, the official said.
Alexandra Kusminova pets her cat, named Mouse, on a bed set up in a restaurant transformed into a shelter for internally displaced people from the eastern region, in Dnipro, Ukraine, April 20, 2022. "We pray every day for everything to be fine, so many people and children have died. For what? Why this war?" asks the 61-year-old woman, who left her home with her daughter and granddaughter, fleeing the Russian attacks in Avdiivka.
Leo Correa/AP
-ABC News' Luis Martinez
Apr 21, 2022, 1:14 PM EDT
Mariupol mayor thinks city will hold out
Mariupol Mayor Vadym Boychenko told ABC News he thinks his city will hold out, saying Russian forces have "been fighting our boys for 57 days and they still can’t win."
The mayor's comments come hours after Russian President Vladimir Putin declared that his siege of Mariupol had been a success, congratulating his defense minister and thanking Russian troops. Putin also ordered troops to abandon their assault on the Azovstal Iron and Steel Works plant, the last holdout for Ukrainian troops in the port city.
Boychenko said 100,00 civilians remain, including 1,000 in the steel plant.
Smoke rises above a plant of Azovstal Iron and Steel Works company during Ukraine-Russia conflict in the southern port city of Mariupol, Ukraine, April 20, 2022.
Alexander Ermochenko/Reuters
President Joe Biden also pushed back on Putin's claim that Russia has control over Mariupol, saying at a news conference Thursday, "There is no evidence yet that Mariupol has completely fallen."
People fleeing fighting in the city of Mariupol meet with relatives and friends as they arrive at a registration center for internally displaced people in Zaporizhzhia on April 21, 2022.
Ed Jones/AFP via Getty Images
-ABC News' James Longman
Apr 21, 2022, 12:51 PM EDT
19 Ukrainians released from Russian captivity in 2nd second prisoner swap this week
Ukrainian Deputy Prime Minister Iryna Vereshchuk said 19 Ukrainians, 10 military and nine civilians, have been released from Russian captivity in the second prisoner swap this week.
-ABC News' Alexandra Faul
Apr 21, 2022, 11:17 AM EDT
Putin claims 'success' in Mariupol siege
Russian President Vladimir Putin declared on Thursday that his siege of Mariupol had been a success, congratulating his defense minister and thanking Russian troops.
"The completion of the combat work to liberate Mariupol is a success," Putin said. “I congratulate you. Convey words of gratitude to the troops."
A service member of pro-Russian troops stands next to a military vehicle with the letter "Z" painted on it, in the southern port city of Mariupol, Ukraine, April 20, 2022.
Alexander Ermochenko/Reuters
Putin’s claim of victory came as he ordered troops to abandon their assault on the Azovstal Iron and Steel Works plant, the last holdout for Ukrainian troops in the port city.
A Ukrainian commander of the regiment at the site said Ukrainian troops there are ready to surrender, if their safety can be guaranteed by a third party and they are allowed to take the bodies of their dead with them.
Ukrainian President Volodymyr Zelenskyy's office called for negotiations inside Mariupol to get anyone left in the factory out of the area alive.
At a news conference Thursday, President Joe Biden pushed back on Putin's claim that Russia has control over Mariupol.
"There is no evidence yet that Mariupol has completely fallen," Biden said.
