British Prime Minister David Cameron has compared Vladimir Putin's Russia to Nazi Germany, before a face-to-face meeting with the Russian leader at the G20 Summit in Australia.
"Russian action in Ukraine is unacceptable. We have to be clear about what we are dealing with. It is a large state bullying a smaller state in Europe.
"We have seen the consequences of that in the past and we should learn the lessons of history and make sure we don't let it happen again," he said during a press conference with Australian Prime Minister Tony Abbott.
"You can see that with what's happened to the Rouble, what's happened to the Russian stock-market. We should use those sanctions in response to Russian action," Cameron added.
"I would still hope the Russians would see sense and recognise that they should allow Ukraine to develop into an independent and free country.
"But if they don't take that approach the relationship that Britain has with Russia, the European Union has with Russia will be very different," he continued.
"If Russia takes a positive approach towards Ukraine's freedom we could see those sanctions removed. If Russia continues to make matters worse we could see those sanctions increase. It's as simple as that."
Cameron has made the comparison between Hitler's march across Europe and Russian interference in eastern Europe before.
Earlier this year, Italian outlet La Repubblica reported that Cameron privately compared appeasement of Hitler at the 1938 Munich conference with the expansionist actions of Putin's Russia, in its former Soviet sphere, to other European Union leaders.