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 25, 2022, 2:14 PM EDT
UN secretary-general heading to Moscow for Lavrov, Putin meetings
United Nations Secretary-General António Guterres is traveling on Monday to Moscow, where on Tuesday he will have a working meeting and lunch with Russian Foreign Minister Sergey Lavrov followed by a meeting with Russian President Vladimir Putin, a deputy spokesperson for the secretary-general said.
On Thursday, Guterres will visit Ukraine where he'll meet with Ukrainian President Volodymyr Zelenskyy and Ukrainian Foreign Minister Dmytro Kuleba.
A firefighter stands next to an apartment building damaged in Odesa, Ukraine, April 23, 2022.
Max Pshybyshevsky/AP
-ABC News' Christine Theodorou
Apr 25, 2022, 1:25 PM EDT
About 15,000 Russian troops killed in Ukraine war
About 15,000 Russian troops have been killed since the Ukraine invasion began, British Defense Secretary Ben Wallace told Members of Parliament on Monday, according to the British Press Association.
Russia has lost more than 60 helicopters and fighter jets, and over 2,000 of Russia's armored vehicles have been destroyed or captured, Wallace added.
An armored vehicle of pro-Russia troops is seen in the street of the southeastern port city of Mariupol, Ukraine, on April 11, 2022, amid Russia's invasion of Ukraine.
Chingis Kondarov/Reuters
Apr 25, 2022, 9:25 AM EDT
Biden announces nominee for ambassador to Ukraine
President Joe Biden is nominating Bridget Brink to serve as U.S. ambassador to Ukraine, he announced Monday.
Brink is currently the U.S. ambassador to the Slovak Republic and previously served as senior adviser and deputy assistant secretary in the State Department's Bureau of European and Eurasian Affairs.
"Brink spent her twenty-five-year career in the Foreign Service focused on advancing U.S. policy in Europe and Eurasia," Biden's statement said.
Apr 25, 2022, 6:13 AM EDT
Blinken says Russia 'already failed' to achieve war goals
U.S. Secretary of State Antony Blinken on Monday said Russia had "already failed" to achieve its stated goals in Ukraine.
"In terms of Russia's war aims, Russia has already failed," Blinken told reporters in Poland, near the Ukrainian border. "And Ukraine has already succeeded because the principal aim that President Putin brought to this, in his own words, was to fully subsume Ukraine, back into Russia to take away its sovereignty and independence. And that has not happened and clearly will not happen."
Blinken and U.S. Secretary of Defense Lloyd Austin met on Sunday with Ukrainian officials in Kyiv, the capital, becoming the highest-level U.S. officials to visit the war-torn country since Russia invaded in February.
In this image from video provided by the Ukrainian Presidential Press Office on Monday, April 25, 2022, Ukrainian President Volodymyr Zelenskyy, right, and U.S. Secretary of State Antony Blinken shake hands during their meeting in Kyiv, Ukraine.
Ukrainian Presidential Press Office via AP
Topics discussed during their three-hour meeting included defense assistance, further sanctions on Russia and financial support for Ukraine, according to Ukrainian President Volodymyr Zelenksyy's office.
"We appreciate the unprecedented assistance of the United States to Ukraine," Zelenskyy said, according to his office. "I would like to thank President Biden personally and on behalf of the entire Ukrainian people for his leadership in supporting Ukraine, for his personal clear position."
U.S. Secretary of Defense Lloyd Austin and Secretary of State Antony Blinken, attend their meeting with Ukrainian President Volodymyr Zelenskyy on April 24, 2022.
Ukrainian Presidential Press Office via AP
He added, "To thank all the American people, as well as the Congress for their bicameral and bipartisan support. We see it. We feel it."
