US president Donald Trump said he hoped Moscow would "do the right thing" and agree to a 30-day ceasefire after the Russian president made a series of demands for concessions. "Now we're going to see whether or not Russia is there, and if they're not, it'll be a very disappointing moment for the world," Mr Trump said.

After clinging for more than seven months to a gradually shrinking area, Ukraine has seen its position worsen sharply in the past week.