Britain has made clear it expects the US to honour commitments made at the G7 summit in Canada, despite Donald Trump's dramatic repudiation of the final communique.
Mr Trump used Twitter to announce that he was ordering US officials not to endorse the document in response to what he claimed were "false statements" by summit host Justin Trudeau.
His tweet shortly after leaving Charlevoix in Quebec threw into doubt the agreement reached by the US, UK, Canada, France, Germany, Italy and Japan at the end of the two-day gathering.
But Theresa May's official spokesman left no doubt that the Prime Minister continues to regard the communique as operative.
"The communique was agreed by all parties who attended G7," the spokesman told a Westminster press briefing.
"We fully intend to honour it. We would hope that the US would similarly honour the commitments that they have made."
European Commission spokesman Margaritis Schinas used a Latin term "Pacta sunt servanda" - or "agreements must be kept" - as he made clear that Brussels expects Washington to honour its commitments.
Mr Schinas told a Brussels press conference: "The EU stands fully behind the G7 communique agreed in Charlevoix.
"The European Union will continue to stand up for an international rules-based multilateral system.
"The European Commission sticks to the final declaration communique and will take all the necessary action at our level to achieve and promote the objectives set therein.
"For us, pacta sunt servanda. After two days of intense negotiations and an even longer preparatory process at sherpa level, the text reflects the values and policies that the EU stands for and that we will continue together with our partners to defend."
During the summit, Mr Trump accused other states of "robbing" his country through their trade policies and proposed scrapping tariffs across the G7.
And in his tweet after departing Charlevoix, he wrote: "Based on Justin's false statements at his news conference, and the fact that Canada is charging massive Tariffs to our U.S. farmers, workers and companies, I have instructed our U.S. Reps not to endorse the Communique as we look at Tariffs on automobiles flooding the U.S. Market!"