Ukraine war | Russia launches fight for the Donbas

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

The stepped-up assaults began Monday along a broad front of over 480 kilometers, Ukrainian officials said. “The Russian troops have begun the battle for the Donbas,” Ukrainian President Volodymyr Zelenskyy announced in a video address.

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 recognized 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.

Meanwhile, in the besieged southern port city of Mariupol, Denys Prokopenko, commander of the Azov Regiment of the Ukrainian National Guard that was holding out against Russian forces, said in a video message that Russia had begun dropping bunker-buster bombs on the Azovstal steel plant where the regiment was holed up.

The sprawling plant contains a warren of tunnels where both fighters and civilians are sheltering. It is believed to be the last major pocket of resistance in the shattered city.

The capture of Mariupol is seen as key. If Russian forces succeed in taking full control of the city, that could free up nearly a dozen battalion tactical groups for use elsewhere in the Donbas, the U.S. defence official said.

It also would deprive Ukraine of a vital port, and complete a land bridge between Russia and the Crimean Peninsula, seized from Ukraine from 2014.

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