Ukrainian President Volodymyr Zelenskyy said on Monday that Russian forces have started a renewed offensive in eastern Ukraine's Donbas region.
Speaking from Kyiv, Zelenskyy said in an address that Ukraine will continue to fight and defend itself against a Russian attack.
"The Russian troops have begun the battle for the Donbas, for which they have been preparing for a long time. A significant part of the entire Russian army is now concentrated on this offensive," Zelenskyy said in his speech.
"No matter how many soldiers are drawn there, we will defend ourselves. We will fight. We will not give up anything Ukrainian," he added. "And I am grateful to all our fighters, to all our heroic cities in Donbas, to Mariupol, and also to the cities of the Kharkiv region which are holding on, defending the fate of the whole state, repelling the forces of invaders. Rubizhne, Popasna, Zolote, Lysychansk, Severodonetsk, Kramatorsk and all others that have been with Ukraine all these years and forever."
Ukraine's Secretary of the National Security and Defense Council Oleksiy Danilov confirmed in a statement that Russian forces launched a new assault on the region.
"This morning, an active phase of the Russian offensive set off almost along the entire front line, the occupiers tried to break through our defenses," Danilov tweeted on Monday. "Our military is defending, we are not surrendering our territories."
Ukrainian and Western officials had warned that a new Russian offensive in the Donbas region was imminent after Russian President Vladimir Putin's forces failed to capture the capital city Kyiv and withdrew from the country's northern areas.
Over 21,000 people have been killed in the southeastern city of Mariupol, Ukraine, leaving the city on the brink of surrender after a Russian commander issued an ultimatum for the Ukrainian troops to "surrender or die" last week.
According to the Associated Press, Pentagon press secretary John Kirby echoed Zelenskyy's warnings in a press briefing on Monday, saying that Russia had set the stage for an advance in the region "by putting in more forces, putting in more enablers, putting in more command and control capability for operations yet to come."
Last week, Zelenskyy and Kuleba issued a stark warning for the fate of the eastern region, if Ukraine did not receive the air defense systems, artillery and jets that Ukraine asked NATO members for.
"The battle for Donbas will remind you of the second world war," Kuleba told NATO members on Friday.
On Friday morning, more than 50 people were killed in a Russian rocket attack on a train station in Kramatorsk, a town in Donetsk, which is located in the Donbas region.
In an interview with BILD after the train station attack, Zelenskyy maintained that Ukraine would defend it's territory.
"It could be a big war in Donbas — like the world has not seen in hundreds of years," he told BILD reporter Paul Ronzheimer.
This story is developing. Please check back for updates.