Donald Trump has been warned by one of Vladimir Putin's allies that escalation in Ukraine could cause a "world war".

       Oligarch Andrey Melnichenko said Russia would be forced to intervene if it believes the US is exterting too much power in the region.

       He told Danish newspaper Frihedsbrevet, as per translated excerpts reported by Russia's global platform RTVI and the independent outlet Agentsvo: "If the escalation continues under Trump, and the Russian leadership gets the impression that this is a problem that has no solution, it will lead to a world war."

       However, according to Newsweek, Melnichenko also predicted the war could end this year if there is no escalation, with a peace treaty being signed after new presidential elections in Ukraine.

       While he called the war "a tragedy" in the history of both countries, he maintained that Russia would not lose.

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       The billionaire co-founded a fertiliser company and coal producer, and was sanctioned by Italy just weeks into the Russia-Ukraine war.

       Melnichenko, worth an estimated ￡20billion, had his ￡465million superyacht seized by Italian authorities.

       The European Union Council described him as "a member of the closest circle of Vladimir Putin" and accused him of backing policies that threatened Ukraine.

       However, last year he told political commentator Tucker Carlson that he never met Putin in person and had no link to the full-scale invasion of Ukraine, nor any political affiliations.

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       This comes as Mr Trump said he spoke on the phone with the Russian president about ending the war. He told The New York Post that the nearly three-year-long war would "never have happened" if he had been in office in 2022.

       He said that Putin "wants to see people stop dying. All those dead people. Young, young, beautiful people. They’re like your kids, two million of them – and for no reason".

       The US president added: "I hope it’s fast. Every day people are dying. This war is so bad in Ukraine. I want to end this damn thing.

       "Let’s get these meetings going. They want to meet. Every day people are dying. Young handsome soldiers are being killed. Young men, like my sons. On both sides. All over the battlefield."