British Prime Minister Boris Johnson is seeking to retain power in the December 12 election that has been dominated by Brexit -- a contentious subject for which Trump has voiced strong support.

The president backs a "no deal" Brexit, and he has already roiled the election campaign by suggesting last month that the terms of Johnson's current EU divorce deal mean that London could struggle to continue trade with the US.

The White House said in a statement that Trump and First Lady Melania would visit Britain from December 2 to 4, attending both the NATO gathering and a reception hosted by Queen Elizabeth II.

NATO leaders face a difficult summit after French President Emmanuel Macron said the bloc was undergoing "brain death" -- prompting a fierce response from German Chancellor Angela Merkel and others.

Macron's comments to The Economist magazine caused much controversy, with Merkel saying his comments were "drastic" and US Secretary of State Mike Pompeo insisting NATO was "important, critical."