Russia has begun major new offensive to seize eastern Ukraine, Zelensky says as ‘explosions heard along entire front’

UKRAINE'S President Volodymyr Zelensky said last night that the long-feared "battle for the Donbas" is finally underway.

Explosions were heard along the entire front as Vladimir Putin launched a major new offensive to seize control of the east.

Ukrainian outlets reported a series of explosions in Kharkiv, Nikolaev and in the suburbs of Donetsk.

And videos on social media appeared to show a blitz on towns as anti-aircraft fire lit up the night sky.

Zelensky's comments follow warnings from other senior officials that Russia has begun its assault on the eastern region on Monday.

In a video address he said: "We can now confirm that Russian troops have begun the battle for the Donbas, which they have been preparing for a long time.

"A large part of the Russian army is now dedicated to this offensive."

The brave Ukrainian leader refused to be cowed by the latest Russian attack, saying: "No matter how many Russian soldiers are brought here, we will fight. We will defend ourselves."

Zelensky's chief of staff said the assault on the Donbas marked the start of the "second phase" of the war.

It comes after fighting has stepped up in the Luhansk and Donetsk regions which make up the Donbas.

According the head of the Luhansk region, at least four people were killed as the city of Kreminna fell into enemy hands overnight.

And earlier today four people were killed by Russian shelling in the Donetsk area says the region's governor.

The Donbas has seen heavy fighting between Ukrainian forces and pro-Russian separatists since 2014. 

Sergei Gaidai, the governor of the Luhansk region said on Facebook: "It's hell. The offensive has begun, the one we've been talking about for weeks.

He said fighting was "constant" in the cities of Rubizhne and Popasna.

Meanwhile today, Russia began dropping bunker-busting bombs on a steel plant in Mariupol where Ukrainians are refusing to surrender, officials said.

Hero defenders are using underground tunnels to stage a last stand against the Russian onslaught.

The head of the police told Mariupol television that many civilians including children are hiding in the plant but it is still getting bombed relentlessly.

The southern port has been besieged since the early days of the war with large parts of it reduced to rubble by Putin's troops.

The attacks follow the continued brutal shelling of Lviv where casualties have risen.

After the humiliating sinking of the flagship of Russias Black Sea Fleet last week, the Kremlin had vowed to step up airstrikes in response.