Donald Trump has said he is "very angry" and "pissed off" with Russian President Vladimir Putin after weeks of attempting to negotiate a ceasefire in Ukraine.

In an NBC News interview, the US president said he was angry with Putin for attacking Ukrainian President Volodymyr Zelensky's credibility, and threatened to impose a 50% tariff on countries buying Russian oil if he did not agree to a ceasefire.

"If Russia and I are unable to make a deal on stopping the bloodshed in Ukraine, and if I think it was Russia's fault, which it might not be...I am going to put secondary tariffs... on all oil coming out of Russia," he said.

The comments mark a shift in Trump's tone toward Putin and Russia.

The White House did not immediately respond to a request for comment.

European leaders had worried that Trump was cosying up to Putin as negotiations on a ceasefire in Ukraine continued.

Over the past six weeks, Trump has harangued Zelensky in the Oval Office and demanded numerous concessions from Ukraine's president. In turn, he has flattered Putin and largely given in to the Russian president's demands.

This appears to be a departure from that dynamic. It is the first time the US has seriously threatened Russia with consequences for dragging its feet in ceasefire negotiations, which would seem to put the diplomatic ball back in Moscow's court.

NBC News reported that, in a 10-minute phone interview, Trump said he was very angry and "pissed off" when Putin criticised the credibility of Zelensky's leadership, although the president has himself called Ukraine's leader a dictator and demanded that he hold elections.

"You could say that I was very angry, pissed off, when... Putin started getting into Zelensky's credibility, because that's not going in the right location," Trump said.

"New leadership means you're not gonna have a deal for a long time," he added.

In the same interview, Trump said he was "not joking" when he said he would not rule out seeking a third term in the White House, despite it being prohibited by the US Constitution.

"A lot of people want me to do it," Trump said. "But, I mean, I basically tell them we have a long way to go."

When speaking about Putin, Trump said that the Kremlin knew of his anger, but noted that he had "a very good relationship" with the Russian leader and "the anger dissipates quickly... if he does the right thing".

If Russia does not follow through with a ceasefire, Trump threatened to target its economy further if he thought it was Putin's fault.

"There will be a 25% tariff on oil and other products sold in the United States, secondary tariffs," Trump said, noting that the tariffs on Russia would come in a month without a ceasefire deal.

Secondary tariffs could constitute up to 50% on goods entering the US from countries still buying oil from Russia. The biggest such buyers by a long margin are China and India.

Zelensky wrote on social media following the interview that "Russia continues looking for excuses to drag this war out even further".

He said that "Putin is playing the same game he has since 2014", when Russia unilaterally annexed the Crimean peninsula.

"This is dangerous for everyone, and there should be an appropriate response from the United States, Europe, and all our global partners who seek peace."

Trump said he would speak to Putin later in the week.

Russia launched a full-scale invasion of its neighbour, Ukraine, in February 2022. It currently controls about 20% of Ukrainian territory.

Over 100,000 people fighting for Russia's military have now died as the war in Ukraine enters the fourth year, according to data analysed by BBC Russian, independent media group Mediazona and volunteers who have been counting deaths since February 2022.

Ukraine last updated its casualty figures in December 2024, when President Volodymyr Zelensky acknowledged 43,000 Ukrainian deaths among soldiers and officers. Western analysts believe this figure to be an underestimate.