German Chancellor Angela Merkel and her cabinet colleagues have been critical of the U.S. President in recent days, after he refused to reiterate the principle of collective security that binds the NATO partners.

President Donald Trump on Tuesday ratcheted up tensions with Germany with a fresh tweet blaming the key ally for not spending enough on defence and for America’s trade deficit. “We have a MASSIVE trade deficit with Germany, plus they pay FAR LESS than they should on NATO & military,” the U.S. president said on Twitter. “This will change,” he added amid a raging domestic debate in the U.S on the President’s first official tour of Europe last week that many critics say has undermined key partnerships.

German Chancellor Angela Merkel and her cabinet colleagues have been critical of Mr. Trump in recent days, after he refused to reiterate the principle of collective security that binds the North Atlantic Treaty Organization (NATO) partners. Mr. Trump also indicated that the U.S under him may withdraw from the Paris climate agreement. Ms. Merkel said “days when Europe could completely count on others are over to a certain extent.”

“We Europeans truly have to take our fate into our own hands,” she said on Sunday and echoed the sentiment again, during her press conference with Prime Minister Narendra Modi. Mr. Trump’s tweet came soon after the Modi-Merkel presser was over.

"The Germans are bad, very bad," Mr. Trump had told European Union leaders last week, according to reports in the German press."See the millions of cars they sell in the U.S., terrible. We will stop this,” the President said. His comments on climate change and defence spending also left European partners in the lurch.

Germany's trade surplus with the U.S is growing. It rose to 252.9 billion euros in 2016, growing from 244.3 billion euros in 2015. Germany has the third largest trade surplus with the U.S, after China and Japan.

Many presidents, including Barack Obama have complained that European partners were “free-riding” on the U.S for defence, but Mr. Trump has raised the rhetoric to a different level altogether. In 2006, NATO members pledged to spend at least two percent of the GDP on defence and they reiterated the pledge in 2014, after Mr. Obama pushed for it. Only five members of the alliance met that threshold in 2016 . The U.S is particularly peeved at Germany which spends only 1.2 percent of its GDP on defence, while the U.S spends 3.6 percent.