The 'battle for Donbas' has begun as Russian forces launch an all-out onslaught of eastern Ukraine.
Vladimir Putin 's war machine has commenced its bombardment of the east with chilling footage posted on social media showing the night sky lit-up amid the relentless fresh shelling of cities.
Kremlin forces launched their long-anticipated offensive through the east of Ukraine in what is being seen as the second phase of the conflict, beginning from Monday night.
Confirming Russia's intent, the Kremlin's defence minister Sergei Shoigu said today its forces are "methodically carrying out" plans to "liberate" two breakaway regions in eastern Ukraine.
Footage on social media appears to show repeated heavy shelling centred in the regions of Donetsk and Luhansk while Ukrainian media reported some powerful explosions in the cities of Marinka, Slavyansk and Kramatorsk.
Ukrainian officials and media also said explosions were heard in Kharkiv in the northeast of Ukraine, Mykolaiv in the south and Zaporizhzhia in the southeast.
The Donbas region has been the aim point of Russia's campaign to destabilise Ukraine since 2014, when Moscow set up separatist "people's republics" in Luhansk and Donetsk.
Air raid sirens were also going off in main centres near the front line.
Ukrainian President Volodymyr Zelensky said Russia had begun the "Battle of Donbas" and that a "very large part of the entire Russian army is now focused on this offensive".
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"No matter how many Russian troops they send there, we will fight. We will defend ourselves," he said in a video address.
Zelensky's chief of staff, Andriy Yermak, assured Ukrainians their forces could hold off the offensive in "the second phase of the war".
"Believe in our army, it is very strong," he said.
There was also fresh fears for Mariupol as Russia launched an offensive against the Azovstal steelworks, said to house the last remaining Ukrainian freedom fighters in the besieged city.
Ukraine's top security official, Oleksiy Danilov, said Russian forces attempted to break through Ukrainian defences "along almost the entire front line of Donetsk, Luhansk and Kharkiv regions".
Shoigu was quoted as saying: "The plan to liberate the Donetsk and Lugansk People's Republics is being methodically carried out.
"The United States and Western countries it controls are doing everything to drag out the special military operation as
much as possible.
"The increasing volume of foreign arms supplies clearly demonstrates their intentions to provoke the Kyiv regime to fight to the last Ukrainian standing."
It comes amid claims by Russia it has hit more than 1,000 targets in Ukraine with missiles and airstrike while on the ground its troops have engaged in street fighting, bringing terror to the Donbas region.
Driven back by Ukrainian forces in the north, Russia has refocused its ground offensive in the two eastern provinces known as the Donbas, while launching long-distance strikes at other targets including the capital, Kyiv.
Donbas has been the focal point of Russia's campaign to destabilise Ukraine, starting in 2014 when the Kremlin used proxies to set up two separatist "people's republics" in the ex-Soviet state. It is also home to much of Ukraine's industrial wealth, including coal and steel.
Russia's defence ministry said it had hit hundreds of military targets in Ukraine overnight.
At the same time the governor of the Russian province of Belgorod said on Tuesday that Ukrainian forces have struck a village near Russia's border with Ukraine, wounding one resident.
It was not immediately clear whether the strike on the village of Golovchino that figured in posts by governor Vyacheslav Gladkov on messaging app Telegram was carried out by artillery, mortars, missiles or was an aerial attack.
This month, Russia accused Ukraine, which it invaded in late February, of a helicopter attack on a fuel depot in Belgorod, as well as of shelling villages there several times, and firing missiles at an ammunition depot.
Russia calls its action in Ukraine a "special military operation".
