The UK's defence secretary warned that Russia's presence in Ukraine could become a "cancerous growth" as Putin looks to consolidate his position in the country.
Ben Wallace said the West must resist Russian efforts to hold onto those parts of Ukraine that they have a foothold in.
Wallace, who is being talked up as a potential successor to Boris Johnson, said that Putin's forces should be forced out of Ukrainian territory.
He told Sky News that Putin may want to consolidate what he has. It was very hard for people to move them out of those fortified positions because of the growth within the country of Ukraine.
If we want this to not happen, we have to help Ukraine get the limpet off the rock.
The international community believes that Russia should leave Ukraine. Russia was condemned by the international community for its invasion of the peninsula. We have always said that Russia should leave the Ukraine.
He conceded there was a long way to go before Ukraine could take back the peninsula.
The first thing to do is to get Russia out of where they are now.
Wallace said that he was comfortable with British-supplied locations being used forlogistics in Russian territory, and that it was legitimate under international law.
He said that Britain is assisting and finding weaponry for the Ukrainians, which is used by the Russians.
James Heappey, a junior defence minister, rubbished the claims that NATO was fighting a proxy war with Russia.
If Putin succeeds, there will be untold further misery across Europe and terrible consequences across the globe, said the Foreign Secretary.
The minister said that what was happening in Ukraine was a war because of the wider implications.
Some argue we shouldn't provide heavy weapons for fear of provoking something worse, but my view is that inaction would be the greatest provocation.