Donald Trump is “obviously very frustrated” with Ukraine’sVolodymyr Zelenskyy, according to the US national security adviser.

The US president has been attempting to negotiate a peace deal with Russia to end its war against Ukraine – and trying to pressure Kyiv into making serious concessions, like ceding occupied territory to Moscow, in the process.

After Trump shocked the west by arranging early negotiations with Russia – and by not inviting Ukraine or Europe to the table – the president then falsely blamed Ukraine for starting the war earlier this week.

Zelenskyy hit back by telling Trump he lives in a Russian-created “disinformation space”. The US president responded by calling him a “dictator” after Kyiv postponed its 2024 presidential elections due to Russia’s invasion.

Asked about this war of words on Thursday, Trump’s national security adviser Mike Waltz said: “President Trump is obviously very frustrated right now with President Zelenskyy.”

He added: “Some of the rhetoric coming out of Kyiv, and frankly, insults to President Trump were unacceptable.”

He then slammed Zelenskyy for rejecting a plan for the president to “co-invest” in mining Ukrainian natural resources in exchange for the financial and military support the US has given to Kyiv over the course of the war.

Asked if, like Trump, Waltz saw Zelenskyy as a “dictator”, the senior official did not respond directly.

The US president’s informal adviser, billionaire and tech tycoon Elon Musk, joined Trump in his attacks on the beleaguered Ukrainian president last night.

He claimed on X that Zelenskyy is actually “despised by the people of Ukraine”.

“If Zelenskyy was actually loved by the people of Ukraine, he would hold an election,” Musk wrote.

“He knows he would lose in a landslide, despite having seized control of ALL Ukrainian media, so he cancelled the election.

“I challenge Zelenskyy to hold an election and refute this. He will not. President Trump is right to ignore him and solve for peace independent of the disgusting, massive graft machine feeding off the dead bodies of Ukrainian soldiers.”

Trump also claimed Zelenskyy’s approval rating was at 4%, but it is actually above 50%.

The Ukrainian president overlooked these tensions last night and said he had a “productive meeting” with the US envoy for the war, Keith Kellogg.

Writing on X, he said they had a “good discussion” and expressed his gratitude for all the US’s assistance.

But, Zelenskyy’s spokesman Serhii Nikiforov still noted that the scheduled media briefing between the two was cancelled at the US’s request. No explanation was offered.

Meanwhile, the Financial Times has reported that the US is pushing back on calling Russia an aggressor in a joint G7 statement to mark the third anniversary of Vladimir Putin’s invasion.

Western allies have used such statements since Russia began to threaten Ukraine’s sovereignty in early 2022. Last year’s statement mentioned “aggression” from Moscow five times.

The US vice-president JD Vance also laid into Zelenskyy last night at Conservative Political Action Conference (CPAC), saying: “His country wouldn’t exist without the generosity of the United States of America. Say thank you. It’s stupid.”

He added: “Badmouthing Trump in public will not change his mind. Zelenskyy needs better consultants.”