Russian President Vladimir Putin's "special military operation” into Ukraine began on Feb. 24, with troops crossing the border from Belarus and Russia. Moscow's forces have since been met with “stiff resistance” from Ukrainians, according to U.S. officials.
Russian forces retreated last week from the Kyiv suburbs, leaving behind a trail of destruction. After graphic images emerged of civilians lying dead in the streets of Bucha, U.S. and European officials accused Russian troops of committing war crimes.
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.
Mar 29, 2022, 6:12 AM EDT
Ukraine warns delegation not to eat or drink at talks
Ukraine is warning its delegation against eating or drinking while attending in-person peace talks with Russian negotiators, amid fears of potential poisoning.
"I advise to everyone who's going to any negotiations with Russia, not to eat or drink anything, and also not to touch any surfaces," Ukrainian Foreign Minister Dmytro Kuleba said in a statement Tuesday.
Deputy head of Ukraine's presidential office Kyrylo Tymoshenko, right, and Ukrainian presidential adviser Mykhailo Podolyak, left, wait for the beginning of talks with Russian negotiators in Istanbul, March 29, 2022.
Ukrainian Presidential Press Service/Handout via Reuters
The warning came a day after The Wall Street Journal reported, , citing unnamed sources, that Russian oligarch Roman Abramovich and two Ukrainian negotiators had suffered symptoms of suspected poisoning following peace talks in Kyiv in early March.
-ABC News' Julia Drozd
Mar 29, 2022, 3:22 AM EDT
Talks between Russia, Ukraine begin in Turkey
The latest round of in-person peace negotiations between Russian and Ukrainian delegations kicked off in Istanbul on Tuesday morning, with Turkish President Recep Tayyip Erdogan in attendance.
Erdogan addressed both sides with a brief speech before the talks began.
"Establishing a cease-fire and peace as soon as possible will be to everyone's benefit. We think that we've entered a period where we need to achieve concrete results from negotiations," Erdogan said. "As members of the delegations, you've taken on a historic responsibility. The whole world is awaiting the good news that will come from you."
Turkey's President Recep Tayyip Erdogan gives a speech to welcome the Russian, left, and Ukrainian, right, delegations ahead of their talks in Istanbul on March 29, 2022.
Turkish Presidency via AP
Footage showing the start of the meeting was broadcast by Russian state-backed television channel RT.
Tuesday's negotiations are taking place in Dolmabahce Palace in the Besiktas district of Turkey's capital, according to Turkish state-run news agency Anadolu Agency. It's the first face-to-face talks to take place between Russia and Ukraine in more than two weeks.
Mar 28, 2022, 6:44 PM EDT
Russian troops 'pushed away from Kyiv': Zelenskyy
Ukraine President Volodymyr Zelenskyy said during his evening address Monday that Irpin was liberated and Russian forces have been "pushed away from Kyiv."
"The occupiers are pushed away from Irpin. Pushed away from Kyiv," he said.
However, he said Russian troops still control the north of Kyiv.
"They are trying to restore the destroyed units. The level of their losses, even at 90%, is not an argument for them to stop. Hundreds and hundreds of units of burned and abandoned enemy equipment do not convince them that this will happen to everyone," he said.
Zelenskyy also said the situation in the Chernihiv, Sumy, Kharkiv regions, along with Donbas and southern Ukraine, remains tense.
"This is a ruthless war against our nation, against our people, against our children. As of today, 143 children are known to have died," Zelenskyy said Monday.
-ABC News' Christine Theodorou
Mar 28, 2022, 4:00 PM EDT
Biden says he 'was expressing moral outrage' with comment that Putin 'cannot remain in power'
President Joe Biden told reporters Monday that when he said in Poland this weekend that Russian President Vladimir Putin "cannot remain in power," he "was expressing moral outrage that I feel," adding, "I make no apologies for it."
President Joe Biden speaks about Russian President Vladimir Putin and Russia's invasion of Ukraine after unveiling his proposed budget for fiscal year 2023 in the State Dining Room of the White House, on March 28, 2022, in Washington, D.C.
Patrick Semansky/AP
Biden did not dispute when a questioner noted the line had not been in his prepared remarks.
"The last part of the speech was talking to the Russian people, telling them what we thought. I was communicating this to not only the Russian people but the whole world. This is -- this is just stating a simple fact that this kind of behavior is totally unacceptable. Totally unacceptable. And the way to deal with it is to strengthen and put -- keep NATO completely united and help Ukraine where we can," Biden said.
An aerial view of a banner saying "children" in Russian language is seen by the entrance of the Slowaskiego Theatre as a sign of solidarity with the Ukrainian victims of Mariupol Theatre that was bombed by Russians, March 29, 2022, in Krakow, Poland.
Omar Marques/Getty Images
"I want to make it clear, I wasn't then, nor am I now, articulating a policy change," Biden said.
"The last thing I want to do is engage in a land war or a nuclear war with Russia," he said. "That's not part of it. I was expressing my outrage at the behavior of this man."
Biden said that if Putin "continues on this course that he's on, he is going to become a pariah worldwide."
Halyna Falko looks at the destruction caused after a Russian attack inside her house near Brovary, on the outskirts of Kyiv, Ukraine, on March 28, 2022.
Rodrigo Abd/AP
He said he didn't think his comments complicated diplomatic efforts, but that it is Putin’s actions that are complicating the situation.
"He shouldn't remain in power. Just like, you know, bad people shouldn't continue to do bad things. But it doesn't mean we have a fundamental policy to do anything to take Putin down in any way," Biden said.
The president said "it’s ridiculous" to think his remark was a statement of U.S. policy.
"People like this shouldn't be ruling countries, but they do. The fact they do doesn't mean I can't express my outrage about it," he said.
Biden told ABC News that he’s confident Putin won’t view his remarks as an excuse for escalation.
"The idea that he is going to do something outrageous because I called him for what he was and what he's doing, I think is just not rational," Biden said.
