WASHINGTON • US President Donald Trump has written sharply worded letters to the leaders of Nato allies, including Germany, Belgium, Norway and Canada, taking them to task for spending too little on their own defence and warning that the US is losing patience with their failure to meet security obligations shared by the alliance.
The letters are the latest sign of acrimony between Mr Trump and US allies as he heads to a Nato summit meeting next week in Brussels that will be a closely watched test of his commitment to the trans-Atlantic alliance after he has repeatedly queried its value and claimed its members are taking advantage of the US.
They raised the prospect of another bitterly contentious confrontation between Mr Trump and US allies after his blowup at the Group of Seven gathering in Quebec last month, and highlighted the worries of European allies that far from projecting solidarity in the face of threats from Russia, their meeting will highlight divisions instead.
"As we discussed during your visit in April, there is growing frustration in the United States that some allies have not stepped up as promised," Mr Trump wrote to Chancellor Angela Merkel of Germany in a particularly pointed version of the letter, according to someone who saw it and shared excerpts with The New York Times.
"Continued German underspending on defence undermines the security of the alliance and provides validation for other allies that also do not plan to meet their military spending commitments, because others see you as a role model."
In language that is repeated in letters to the leaders of other countries, including Prime Minister Justin Trudeau of Canada and Prime Minister Erna Solberg of Norway, Mr Trump said he understands the "domestic political pressure" brought to bear by opponents boosting military expenditures, noting that he has expended "considerable political capital to increase our own military spending".
But Mr Trump seemed to suggest the US might adjust its military presence worldwide if its allies do not step up.
"It will, however, become increasingly difficult to justify to American citizens why some countries do not share Nato's collective security burden while American soldiers continue to sacrifice their lives overseas or come home gravely wounded," Mr Trump wrote to Dr Merkel.
Mr Trump's letter to Mr Trudeau was reported in June by iPolitics in Canada, and the existence of others was reported this past week by Foreign Policy. Media in Belgium and other Nato countries have since confirmed their leaders got similar letters.
Mr Trump was referring to the fact that many Nato allies are not living up to the commitment they made at their Wales summit meeting in 2014 to spend 2 per cent of their GDP on national defence.