US President Donald Trump has said he was "very angry" with Russian leader Vladimir Putin, NBC reported, marking a sharp change of tone as Washington seeks to end the war in Ukraine.
NBC's Kristen Welker said Mr Trump had called her to express his anger over Mr Putin questioning Ukrainian President Volodymyr Zelensky's future as a leader - something that Mr Trump himself has done.
Ms Welker, on her NBC show 'Meet The Press', quoted directly from an early-morning telephone conversation with the president.
Mr Trump said that "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" then he would impose "secondary tariffs on all oil coming out of Russia".
Ms Welker said Mr Trump told her "I was very angry, pissed off" over Mr Putin's recent comments about Mr Zelensky's credibility and talking about new leadership in Ukraine.
President Trump has been pushing for a speedy end to the more than three-year war since taking office, but his administration has failed to reach a breakthrough despite talks with both sides.
Mr Putin rejected a joint US-Ukrainian plan for a 30-day ceasefire and on Friday suggested Mr Zelensky be removed from office as part of the peace process.
Ukraine has accused Russia of dragging out talks with no intention of halting its offensive, with a fresh attack over the weekend on the northeastern border city of Kharkiv.
Mr Trump told NBC that Mr Putin knows he is angry, but said that he has "a very good relationship with him" and "the anger dissipates quickly ... if he does the right thing".
Explaining the secondary tariffs threat, Mr Trump told NBC "that would be that if you buy oil from Russia, you can't do business in the United States".
"There will be a 25% tariff on all oil, a 25 to 50 point tariff on all oil," he added, without giving further details.
Mr Trump's remarks to NBC suggest he could take similar action against US imports from countries that buy oil from Russia, a move that could hit China and India particularly hard.
The US has not imported any Russian barrels of crude oil since April 2022, according to US government data.
Before that, US refiners bought inconsistent volumes of Russian oil, with a high of 98.1 million barrels in 2010 and A low of 6.6 million in 2014, according to a review of EIA data since 2000.
India has surpassed China to become the biggest buyer of seaborne Russian crude, which comprised about 35% of India's total crude imports in 2024.
Mr Trump also said he could hit buyers of Iranian oil with secondary sanctions if Tehran did not reach an agreement to end their nuclear weapons program.
Mr Trump's comments followed a day of meetings and golf with Finnish President Alexander Stubb, during Mr Stubb's surprise visit to Florida.
Mr Stubb's office said he told the president a deadline needs to be set for establishing a Russia-Ukraine ceasefire to make it happen and suggested 20 April since Mr Trump would have been in office then for three months.
US officials have been separately pushing Ukraine to accept a critical minerals agreement, a summary of which suggested the US was demanding all Ukraine's natural resources income for years.
Mr Zelensky has said Ukraine's lawyers need to review the draft before he can say more about the US offer.
Mr Trump's latest tariff threats would add to the challenges already facing China, India and other countries through trade measures imposed during his first two months in office, including duties on steel, aluminium and cars.
More duties on imports from the countries with the largest trade surpluses are slated to be announced on Wednesday.
William Reinsch, a former senior Commerce Department official now at the Center for Strategic and International Studies, said the haphazard way Mr Trump was announcing and threatening tariffs leaves many questions unanswered, including how US officials could trace and prove which countries were buying Russian oil.
Warming ties between the United States and Russia since Mr Trump's return to office and his threats to stop supporting Ukraine have bolstered Russia on the battlefield as it pursues its floundering invasion.
Mr Putin, in power for 25 years and repeatedly elected in votes with no competition, has often questioned Mr Zelensky's "legitimacy" as president, after the Ukrainian leader's initial five-year mandate ended in May 2024.
Under Ukrainian law, elections are suspended during times of major military conflict, and Mr Zelensky's domestic opponents have all said no ballots should be held until after the conflict.
President Trump has himself had rocky relations with Mr Zelensky, calling him a "dictator" and clashing with him live on camera at the White House last month.
"For too long now, America's proposal for an unconditional ceasefire has been on the table without an adequate response from Russia," Mr Zelensky said in his evening address yesterday.
"There could already be a ceasefire if there was real pressure on Russia," he added, thanking those countries "who understand this" and have stepped up sanctions pressure on the Kremlin.
Both Moscow and Kyiv agreed to the concept of a Black Sea truce following talks with US officials earlier this week, but Russia said the deal would not enter into force until Ukraine's allies lifted certain sanctions.
