US President Donald Trump has called Germany's trade and spending policies "very bad", intensifying a row between the allies and immediately earning himself the moniker "destroyer of Western values" from a leading German politician
Mr Trump took to Twitter early on Tuesday (local time) in the United States to attack Germany, a day after Chancellor Angela Merkel ramped up her doubts about the reliability of Washington as an ally.
The tit-for-tat row has escalated rapidly after Trump criticised major NATO allies over their military spending and refused to endorse a global climate change accord at back-to-back summits last week.
"We have a MASSIVE trade deficit with Germany, plus they pay FAR LESS than they should on NATO & military. Very bad for US This will change," Mr Trump tweeted on Tuesday.
On Monday, Ms Merkel showed how seriously concerned she is about Washington's dependability under Mr Trump by repeating the message that the times when Europe could fully rely on others were "over to a certain extent".
Those comments, which sent shock waves through Washington, vented Europe's frustration with Mr Trump on climate policy in particular.
Senior German politicians responded swiftly to his tweet.
Martin Schulz, leader of the centre-left Social Democrats, told reporters Mr Trump was "the destroyer of all Western values", adding that the US president was undermining the peaceful cooperation of nations based on mutual respect and tolerance.
Thomas Oppermann, head of the Social Democrats' parliamentary group, told reporters: "Donald Trump makes clear with his tweet that he views Germany as a political opponent."
Ms Merkel on Monday repeated almost word for word her message from Sunday, when she told her Bavarian conservative allies in a packed Munich beer tent that "we Europeans must really take our fate into our own hands".
But she also finessed her message slightly on Monday, stressing that she was a "convinced trans-Atlanticist".
On Tuesday, Ms Merkel repeatedly stressed the importance of trans-Atlantic ties.
Meanwhile, back at the White House, US President Donald Trump's communications director, Mike Dubke, is set to leave after three months in his White House post.
"He has expressed his desire to leave the White House and made very clear he would see through the president's international trip," White House adviser Kellyanne Conway told Fox News on Tuesday (local time), referring to Trump's first overseas trip to the Middle East and Europe that ended on Saturday.
Mr Dubke, a communications firm owner brought into the administration in March, resigned on May 18 though he has not set a last day on the job and is leaving on good terms, according to Axios News, which first reported his departure citing a senior administration official.
His departure comes amid White House plans for a larger strategic shake-up to tackle head-on allegations involving communication between Russia and Mr Trump's presidential campaign, including a "war room" to combat mounting questions and multiple probes.
According to administration officials and persons close to Mr Trump, the president plans to bring in new aides to the White House, adding experienced political professionals including Mr Trump's former campaign manager.
The changes may also include more lawyers to handle the Russia probe as part of the effort to tackle a scandal that has threatened to consume Mr Trump's young presidency.
Other potential changes are also expected to the White House communications office, according to Axios, including fewer on-camera briefings with White House Press Secretary Sean Spicer.
Mr Trump will also take more questions directly from the media, it reported.
In a tweet early on Tuesday, Mr Trump shot back against the Russia probes, writing: "Russian officials must be laughing at the US & how a lame excuse for why the Dems lost the election has taken over the Fake News."
Ms Conway, on Fox News, also played down persistent rumours that Mr Spicer, who has been pilloried on comedy shows, was on his way out. She said he would be back at the podium to brief reporters on Tuesday.