Mariupol fighters 'successful in tying down Russian forces'

KYIV, Apr 20 (BBC/AFP): Ukrainian forces in Mariupol have successfully tied down thousands of Russian soldiers who otherwise would've been redeployed northwards for the main battle in Donbas, according to Professor Malcolm Chalmers, Deputy Director General of the Royal United Services Institute (Rusi).

"Defenders of Mariupol, having lasted so long, have made a significant contribution to the overall war effort - even if they eventually are overwhelmed", he tells the BBC.

"Russian resources are not unlimited and they lost a lot of equipment and people in a failed campaign to take Kyiv," Chalmers adds.

He says Putin's maximum aim remains to replace the Ukrainian government with a regime to his liking - even the total absorption of Ukraine to Russia.

"The battle of Donbas is a case of sequencing - trying to achieve one thing at a time."

He says if Russia is successful in its Donbas assault, "which is possible but not likely", they would then move on to the south to attack Odesa and Kyiv.

"In retrospect, the Russian leadership will believe they made a strategic error trying to fight Ukraine on several fronts at the beginning of the war," Chalmers says.

Izyum may become next Bucha,

with thousands trapped

The city of Izyum - known as the gateway to the Donbas region and the Black Sea - is experiencing fierce fighting as the Russians use it as a staging post to attack towns in the east.

Now, there are fears Izyum will become the next Bucha - where Russia is accused of war crimes against the civilian population, including executions and torture.

Izyum reportedly has the highest concentration of Russian troops in Ukraine.

The strategic city, located 70 miles south-east of Kharkiv, heads into the separatist-controlled east and fell completely to the Russians on 1 April.

While some civilian evacuations were carried out before Russian soldiers invaded, there are around 10,000 to 15,000 people still trapped according to officials.