Ukrainian President Volodymyr Zelensky says a "battle for the Donbas" is underway, after Russia launched its expected major assault on that eastern region.
He said Ukrainians would fight to defend themselves, no matter how many Russian troops were brought there. Zelensky's chief of staff said it marked the start of the war's "second phase".
Russia has been shifting the focus of its war to eastern Ukraine, after setbacks near the capital, Kyiv.
In recent weeks, Moscow's military campaign has refocused on the eastern region of Donbas, which pro-Kremlin separatists have partly controlled since 2014.
"We can now confirm that Russian troops have begun the battle for the Donbas, which they have been preparing for a long time," Ukrainian President Volodymyr Zelensky said on Telegram late Monday.
"No matter how many Russian soldiers are brought here, we will fight. We will defend ourselves."
Ahead of the widely anticipated advance, Ukrainian authorities had urged people in Donbas to flee west to escape.
"The second phase of the war has started," Kyiv's presidential chief of staff Andriy Yermak said.
The Donbas is Ukraine’s mostly Russian-speaking industrial heartland in the east, where Moscow-backed separatists have been fighting Ukrainian forces for the past eight years and have declared two independent republics that have been recognized by Russia.
In recent weeks, the Kremlin declared the capture of the Donbas its main goal of the war after its attempt to storm Kyiv failed. After withdrawing from the capital, Russia began regrouping and reinforcing its ground troops in the east for an all-out offensive.
The offensive got underway after Russia bombarded the western city of Lviv and a multitude of other targets across Ukraine in what appeared to be an intensified bid to grind down the country’s defenses.
The Ukraine military’s general staff said Russian President Vladimir Putin’s forces were increasing assaults in the Luhansk and Donetsk regions — both of which are part of the Donbas — as well as in the area of Zaporizhzhia.
“This morning, almost along the whole front line of the Donetsk, Luhansk and Kharkiv regions, the occupiers attempted to break through our defenses,” Oleksiy Danilov, secretary of Ukraine’s national security council, was quoted as telling Ukrainian media. “Fortunately, our military is holding out. They passed through only two cities. This is Kreminna and another small town.”
He added: “We are not giving up any of our territories.”
If Russia were to conquer all of Donbas, it would give Putin some sort of achievement from Russia's war. The next step would then be to annexe Donbas, just like he did with Crimea after a discredited referendum in 2014.
And if it came before 9 May, he would even be able to celebrate on Victory Day, when Russia's military still marks the defeat of Nazi Germany in 1945.
