Britain's defence ministry said Friday that Moscow's troops have recently captured several villages as they attempt to surround Sievierodonetsk and Lysychansk in the eastern Donbas region, but do not yet have full control of the region.

Johnson told news agency, Bloomberg, that Russian President Vladimir Putin ``at great cost to himself and the Russian military is continuing to chew through ground in Donbas, he's continuing to make gradual, slow but I'm afraid palpable progress.''

He said ``therefore it is absolutely vital that we continue to support the Ukrainians militarily.''

Johnson said long-range multiple-launch rocket systems, or MLRSs, ``would enable them to defend themselves against this very brutal Russian artillery.''

Britain possesses some of the systems, but Johnson did not say whether the U.K. would send any to Ukraine.