The transatlantic diplomatic rift widened on Tuesday as US President Donald Trump responded to criticism from Chancellor Angela Merkel with a new attack on German trade tactics and defence spending.
Trump's spokesman Sean Spicer insisted that the leaders "get on very well" but – as is often the case – his warm words from the White House podium were overshadowed by the president's intemperate tweets.
When Trump returned over the weekend from the first foreign trip of his presidency, his aides hailed the tour as a success and a sign of renewed and bolder US leadership on the world stage.
But, while Trump received a warm welcome in Saudi Arabia and Israel, he left behind a bitter taste in Europe after the Nato summit in Brussels and the G7 get-together of the world's richest powers in Sicily.
European leaders were especially dismayed by Trump's refusal to reaffirm US support for last year's Paris climate change accord and his failure to publicly endorse Nato's mutual defence pledge.
Germany was particularly discomfited, and Merkel wasted no time in warning German voters that the United States can no longer be relied upon as before.
Trump's response came in the early hours of Tuesday when he took to Twitter to once again demand that Germany renegotiate the terms of transatlantic trade and boost its defence spending.
Resume EU trade talks?
Despite the sometimes heated rhetoric, Washington is "open" to resuming talks with the EU on the Transatlantic Trade and Investment Partnership, US Commerce Secretary Wilbur Ross said late Tuesday.
Launched in 2013, negotiations on the TTIP – which would set up a huge free trade area on both sides of the Atlantic – screeched to a halt when Trump was elected on an "America First" platform.
"It makes sense to continue TTIP negotiations and to work towards a solution that increases overall trade while reducing our trade deficit," Ross told CNBC.
"It's no mistake that, while we withdrew from TPP (the Trans-Pacific Partnership trade deal with Pacific Rim economies) we did not withdraw from TTIP," Ross said.
When Trump took office in January one of his earliest moves was to exit the TPP, which Washington had signed with 11 countries in the Asia-Pacific region, including Japan and Australia.
Brussels and Washington failed to get the TTIP deal approved before Trump's predecessor, president Barack Obama, left office.