Intelligence services say around 1,700 Ukrainian soldiers have surrendered from a steel plant in the besieged city of Mariupol.
However there is still an 'unknown number' of fighters left inside.
A British intelligence report also states once Russian troops secure Mariupol they’ll redeploy to the eastern Donbas region.
Ukraine’s president, Volodymyr Zelenskyy, says the occupiers have already 'created hell' there.
"This is a deliberate criminal attempt to kill as many Ukrainians as possible, to destroy as many house, social facilities and enterprises as possible.
"This is what would be qualified as the genocide of the Ukrainian people."