The billionaire is said to have instructed his aides to work out Germany’s debt to the organisation following their meeting earlier this month.
With member countries pledging to contribute two per cent of their GDP to defence in 2014, something only a handful do, Mr Trump has been critical of those who he deems are not paying their fair share.
The bill is said to take into account how much Germany underspent by since 2002, when Chancellor Merkel’s predecessor, Gerhard Schröder, pledged to spend more on defence.
It is said to have come to £250n, with £50n interest added on.
Trump claims the US has been forced to shoulder the financial burden of NATO Merkel meets Trump at the White House Fri, March 17, 2017
U.S. President Donald Trump has welcomed German Chancellor Angela Merkel to the White House in Washington DC
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U.S. President Trump and German Chancellor Merkel hold a joint news conference in Washington
An unnamed German minister was quoted by the Times as saying the bill was “outrageous” and added: “The concept behind putting out such demands is to intimidate the other side, but the chancellor took it calmly and will not respond to such provocations.”
Another source said: “The president has a very unorthodox view on Nato defence spending.
“The alliance is not a club with a membership fee. The commitments relate to countries' investment in their defence budgets."
The billionaire is said to have instructed his aides to work out Germany’s debt
Mrs Merkel is said to be 'ignoring' the bill.
But the White House has denied the claims, with spokesperson Michael Short saying the report was "false”.
Despite aides maintaining the bill does not exist, Donald Trump has been vocal about the perceived sums owed by Germany.
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There is no account where debts are registered with NATO
Ursula von der Leyen
Shortly after Mr Trump's and Mrs Merkel's catastrophic meeting in Washington, where the 70-year-old president refused to shake his counterpart’s hand, he took to twitter to grill Germany over its defence spending.
He posted: “Despite what you have heard from the FAKE NEWS, I had a GREAT meeting with German Chancellor Angela Merkel.
“Germany owes… vast sums of money to NATO & the United States must be paid more for the powerful, and very expensive, defence it provides to Germany!"
The bill is said to take into account how much Germany underspent by since 2002
He claims the US has been forced to shoulder the financial burden of NATO, which he indicated will not continue throwing doubt on the US’ future role in the partnership.
But a day after his twitter tirade, German defence minister Ursula von der Leyen issued a statement to the contrary.
She said: “There is no account where debts are registered with NATO.
“Defence spending also goes into UN peacekeeping missions, into our European missions and into our contribution to the fight against ISIS terrorism.”
Mr Malloch rated the president’s meeting with Mrs Merkel a paltry one out of 10
Mrs Merkel has committed to higher defence spending by Germany, something Mr Trump has been wrangling for.
But the pair’s future working relationship looks uncertain after Mr Trump’s ally, Ted Malloch admitted their meeting was “as frosty as the storm” raging in the US capital at the time.
Mr Malloch rated the president’s meeting with Mrs Merkel a paltry one out of 10, compared to 9.5 for Theresa May.