Donald Trump told former UK Prime Minister Theresa May she was weak and also told German Chancellor Angela Merkel she was "stupid" in separate phone calls, according to CNN citing senior US officials.
Accounts of previous phone calls between the US President and foreign leaders have reportedly been revealed by intelligence and White House officials. Sources were not named in the report.
Officials told the news channel allies were often bullied by Trump during phone calls leaving US officials concerned about national security.
Trump "demeaned and denigrated" May and Merkel, according the report. He is said to have accused Merkel of "being in the pocket of the Russians", and would act unpleasant towards May over matters such as Brexit.
Merkel was reportedly able to stay calm, while May became "flustered, nervous, and intimidated".
In phone calls to Mohammed bin Salman, autocratic heir of Saudi Arabia, and North Korean leader Kim Jong Un, Trump also reportedly gloated about his wealth.
Relations between Berlin and Washington have often been strained during Trump's presidency. Trump has pressed Germany to raise defence spending and accused Berlin of being a "captive" of Russia due to its partial reliance on Russian energy.
German Foreign Minister Heiko Maas told Bild am Sonntag newspaper earlier this month its relationship with the US is "complicated".
"We are close partners in the transatlantic alliance, but it is complicated," Maas said.
Trump also had a spat with May before she left office. In memos leaked in July, the President called her "foolish" for defending Washington Ambassador Kim Darroch after he described Trump's administration as "dysfunctional".
In response to the alleged phone calls, White House press secretary Sarah Matthews told CNN Trump is a "world-class negotiator".
"From negotiating the phase one China deal and the USMCA (United States-Mexico-Canada Agreement) to NATO allies contributing more and defeating ISIS, President Trump has shown his ability to advance America's strategic interests."
The phone call claims appear to reflect allegations by former White House national security adviser John Bolton, who has accused Trump in a book of sweeping misdeeds and said he is not fit for office.
Bolton releasing his book led to the US suing him, seeking to block it from being made public. A judge later denied that bid and the book has since been released.
"While Bolton's unilateral conduct raises grave national security concerns, the Government has not established that an injunction is an appropriate remedy," US District Judge Royce Lamberth said in his ruling.
Reuters / Newshub.