Donald Trump will use his first face-to-face meeting with Angela Merkel this week to put pressure on Germany to "share the burden" of Nato spending, senior US officials have said, in what has been described as a "make or break" meeting between the two leaders.
The US president will also be "candid" with the German chancellor when the pair meet in Washington about the need to reduce America's trade deficit with Germany, in what will be the US president's first meeting with a world leader of whom he has been critical.
"The president believes that all allies must share the burden of Nato spending, and he is heartened that the German government is committed to spending two per cent of GDP," said the official.
"The message has been strong that all allies need to be making progress towards this goal. He does believe Germany as one of the largest economies should be setting an example and leading an example as we do in the US... he is very tough on the issue and has encouraged Europeans to look at increased commitments as well."
The two leaders will also discuss the global economy, the fight against Isil, and ties with Russia and China, laying the groundwork for Trump's visit to Germany in July for a gathering of G20 leaders.
Merkel's visit will take place mid-week, ahead of Taoiseach Enda Kenny's White House visit on Thursday.
The German chancellor has already clashed publicly with the US president, who called her open door refugee policy "insane".
On the German side, there have been deep concerns about Trump's commitment to Nato, and his plan to ban citizens of six predominantly Muslim countries from entering the US.
Prof Anthony Glees, an expert in German politics at the University of Buckingham, said the visit would be "make or break" for Merkel.
"So far Merkel's attitude towards Trump has been seen as passive aggressive, Trump's attitude towards Merkel as active aggressive," he said. "They must cordially agree to disagree on past actions and past words, but to work together. If anything goes wrong the consequences could be devastating both in terms of Germany's domestic politics and the weakness of West in the face of Russian advances.In short, the stakes could hardly be higher."
Peter Navarro, Trump's trade adviser, suggested there would also be very direct talks about the trade deficit.
The $65bn US trade deficit with Germany was "one of the most difficult" trade issues facing Trump, he said, and bilateral discussions were needed to reduce it outside European Union restrictions.
Navarro, director of the new White House National Trade Council, added: "It's a serious issue. Germany is one of the most difficult trade deficits that we're going to have to deal with but we're thinking long and hard about that."
The US is Germany's biggest destination for exports but Trump has warned his administration may impose a 35pc tax on cars BMW intends to make at a new plant in Mexico and sell in the United States.
During the election Trump let loose on Merkel, accusing her of "ruining" Germany with her refugee policy. In January he told Bild that Merkel had made a "catastrophic" error on migration.
Merkel, who had a warm relationship with Trump's predecessor Barack Obama, has in turn been critical of Trump's travel ban and his comments about the media.
In an attempt to build bridges, the White House arranged for Merkel to meet with Mike Pence, the US vice-president, two weeks ago at a security conference in Munich.
"There will be huge pressure from Trump's backroom guys to chum up to Frau Merkel," said Prof Glees. "America needs a big friend in the EU - and for obvious reasons Britain can't be that friend any longer."