Ukrainian President Volodymyr Zelensky. [Source: BBC News]

Ukrainian President Volodymyr Zelensky has accused European countries that continue to buy Russian oil of “earning their money in other people’s blood”.

In an interview with the BBC, President Zelensky singled out Germany and Hungary, accusing them of blocking efforts to embargo energy sales, from which Russia stands to make up to £250bn ($326bn) this year.

There has been a growing frustration among Ukraine’s leadership with Berlin, which has backed some sanctions against Russia but so far resisted calls to back tougher action on oil sales.

“Some of our friends and partners understand that it is a different time now, that it is no longer an issue of business and money,” Mr Zelensky told the BBC from his situation room in Kyiv on Thursday. “That it is an issue of survival.”

The president also reiterated calls for more weapons to be supplied to Ukraine, saying they were not getting supplies fast enough to fend off Russia’s assault.

“The United States, the United Kingdom, some European countries – they are trying to help and are helping,” he said. “But still we need it sooner, sooner and faster. The key word is now.”

Russian troops have in recent weeks pulled back from around Ukraine’s capital, Kyiv, and other central and northern parts of the country – apparently abandoning an attempt to seize all of Ukraine by force.

But there are fears now of a bloody and protracted conflict in the east and south of the country, as Russian President Vladimir Putin refocuses his military campaign there in an effort to seize more territory.

The southern port city of Mariupol – a strategic goal for President Putin – has already been devastated by weeks of Russian artillery bombardment.

President Zelensky told the BBC he thought tens of thousands may have been killed in the city.