A crater and a destroyed home are pictured in the village of Yatskivka, eastern Ukraine. AFP

Russia launched a major offensive in eastern Ukraine, officials in Kyiv say, opening a new phase of its invasion after being thwarted in efforts to capture the capital.

Russian forces have launched their anticipated offensive in eastern Ukraine, attempting to push through defences along almost the entire front line early on Tuesday in what Ukrainian officials described as the second phase of the war.

READ MORE

Missiles strike Lviv, bodies in streets of Mariupol

Kreminna falls as Russians tighten grip on east Ukraine

After days of regrouping and reinforcing, the Russian military began a new and potentially climactic phase of the war in Ukraine by launching its long-feared, full-scale ground offensive to take control of the country's industrial heartland, the Donbas, Ukrainian officials said.

Ukrainian President Volodymyr Zelensky speaks in Kyiv. File photo

Ukrainian President Volodymyr Zelensky said Russia had begun the "Battle of Donbas" in the east and a "very large part of the entire Russian army is now focused on this offensive".

"No matter how many Russian troops they send there, we will fight. We will defend ourselves," he said in a video address on Monday.

The stepped-up assaults began on Monday along a broad front of over 300 miles (480 kilometres), Ukrainian officials said.

Servicemen are seen inside a bunker in Popasna, Ukraine's Donbass region, amid Russian invasion of Ukraine . AFP

“The Russian troops have begun the battle for Donbas,” Zelensky announced in a video address. He said a "significant part of the entire Russian army is now concentrated on this offensive.”

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 no immediate comment from Russia's defence ministry on the latest fighting. The governor of the Russian province of Belgorod said Ukrainian forces had struck a border village wounding one resident.

A burnt van is pictured on the empty way to Popasna, Ukraine's Donbass region. AFP

Moscow-backed separatists have been fighting Ukrainian forces for eight years in the mostly Russian-speaking Donbas and have declared two independent republics that have been recognised by Russia. Russia has declared the capture of the Donbas to be its main goal in the war since its attempt to seize the capital, Kyiv, failed.

"No matter how many Russian troops are driven there, we will fight,” Zelensky vowed. "We will defend ourselves.”

Before the offensive got under way, Russia bombarded the western city of Lviv and other targets in what appeared to be an intensified bid to grind down the country’s defences.

The Ukraine military’s general staff said Russian President Vladimir Putin’s forces had intensified assaults in the Luhansk and Donetsk regions – both part of the Donbas — and in the area of Zaporizhzhia.