President Trump has spent the day attacking Ukraine's President Volodymyr Zelensky, calling him a "dictator" and deepening the rift between the two leaders.

His attacks came after Zelensky, reacting to US-Russia talks in Saudi Arabia from which Kyiv was excluded, said the US president was "living in a disinformation space" governed by Moscow.

Speaking at a Saudi-backed investment meeting in Florida, Trump said the only thing Zelensky "was really good at was playing Joe Biden like a fiddle".

The "dictator" slur quickly prompted criticism from European leaders including German Chancellor Olaf Scholz, who said "it is simply wrong and dangerous to deny President Zelensky his democratic legitimacy".

UK Prime Minister Sir Keir Starmer made it clear he backed Zelensky in a phone call to the Ukrainian president.

A Downing Street spokesperson said Sir Keir "expressed his support for President Zelensky as Ukraine's democratically elected leader".

It was "perfectly reasonable to suspend elections during war time as the UK did during World War Two," the spokesperson added.

Zelensky is due to meet the American envoy for Russia and Ukraine, Keith Kellogg, on Thursday. He said it was crucial that the discussion - and overall co-operation with the US - remains constructive.

In a social media post, Zelensky said that peace could be more secure with the US and Europe.

Zelensky's five-year term of office was due to come to an end in May 2024. However, Ukraine has been under martial law since Russia launched its full-scale invasion in February 2022 and elections are suspended.

Swedish Prime Minister Ulf Kristersson also criticised Trump's use of the word "dictator" while German Foreign Minister Annalena Baerbock called the comments "absurd".

"If you look at the real world instead of just firing off a tweet, then you know who in Europe has to live in the conditions of a dictatorship: people in Russia, people in Belarus," she told broadcaster ZDF.

Speaking in Florida, Trump called Zelensky a "dictator", just hours after using the same word in a Truth Social post about the Ukrainian president.

"He refuses to have elections. He's low in the real Ukrainian polls. How can you be high with every city being demolished?" Trump said.

He also referenced his attempt to get rare-earth minerals from Ukraine, accusing Zelensky's government of "breaking the deal".

His address echoed his wording of the Truth Social post where Trump said Zelensky "has done a terrible job, his country is shattered, and MILLIONS have unnecessarily died." In the meantime, the US was "successfully negotiating an end to the war with Russia," he said.

A White House official said Trump's post was in direct response to Zelensky's "disinformation" comments.

On Tuesday US and Russian officials held their first high-level, face-to-face talks since Russia's full-scale invasion.

The former prime minister of Ukraine, Arseniy Yatsenyuk, told the BBC that Russia was "popping champagne right now" in response to Trump's comments.

"Volodymyr Zelensky is a completely legitimate president," he said. "We cannot hold elections under martial law."

The war of words began with comments made by Trump on Tuesday at a news conference at Mar-a-Lago in Florida, when he blamed Ukraine for the war.

Trump was asked by BBC News what his message was to Ukrainians who might feel betrayed, to which he replied: "I hear that they're upset about not having a seat, well, they've had a seat for three years and a long time before that. This could have been settled very easily."

"You should have never started it. You could have made a deal," Trump added.

Trump did not mention that President Vladimir Putin took the decision to invade Ukraine in February 2022.

Then on Wednesday, Zelensky told reporters in Kyiv: "We are seeing a lot of disinformation and it's coming from Russia. With all due respect to President Donald Trump as a leader... he is living in this disinformation space."

He added that he believed "the United States helped Putin to break out of years of isolation".

Later in the day, the Ukrainian leader said the world faced the choice to be "with Putin or with peace" and announced he would be meeting Washington's Ukraine envoy, Keith Kellogg, on Thursday.

Earlier, Zelensky also rejected Trump's attempts to access Ukraine's rare minerals, saying no security guarantees were offered in exchange.

Trump has attempted to make an issue out of Zelensky's popularity, claiming the Ukrainian president had only a 4% approval rating. But BBC Verify reports that polling conducted this month found 57% of Ukrainians said they trusted the president.

In Wednesday's explosive Truth Social post, Trump also took aim at Europe, saying the war in Ukraine is "far more important to Europe than it is to us".

"We have a big, beautiful ocean as a separation," he said.

Europe had "failed to bring peace" in the region, he added.

Meanwhile, Russian President Vladimir Putin also spoke to reporters, saying he would meet Trump "with pleasure".

For its part, the EU said it would place further sanctions on Russia.

The new sanctions target Russian aluminium and dozens of vessels suspected of illegally transporting oil. They would also disconnect more Russian banks from the global Swift payment system and ban more Russian media outlets from broadcasting in Europe.