German Foreign Minister Frank-Walter Steinmeier, speaking ahead of an EU foreign ministers meeting, said Trump's view on NATO and criticism that allied members weren't paying their fair share has "caused astonishment."
His French counterpart Jean-Marc Ayrault added that the best response to such an interview was simple — Europeans uniting.
In Berlin, Chancellor Angela Merkel said Trump's positions have been "long known" but added: "I think we Europeans have our fate in our own hands."
"I'm personally going to wait until the American president takes office, and then we will naturally work with him on all levels," she told reporters.
Though Trump had made similar comments during his tempestuous election campaign, a repetition of the same points still came as a bit of a surprise since his choice for defense secretary, retired Marine Gen. James Mattis, stressed his support for the alliance in his U.S. congressional confirmation hearings last week.
Trump's views, in an interview with German daily Bild and The Times of London, contradict Mattis, Steinmeier said.
Trump indicated he was indifferent to whether the EU stays together or not, a sharp break from the Obama administration, which encouraged British people to vote to remain in the EU in the June referendum.
"I believe others will leave ... I do think keeping it together is not gonna be as easy as a lot of people think," Trump said in the interview.
The British exit from the EU would "end up being a great thing," he said.
British Foreign Secretary Boris Johnson said it's "very good news that the United States of America wants to do a good free trade deal with us and wants to do it very fast."
Trump was less kind to German industry officials, saying car manufacturers including BMW could face tariffs of up to 35 percent if they set up plants in Mexico instead of in the U.S. and try to export the cars to the U.S.
Such tariffs would make "the American auto industry worse, weaker and more expensive," Sigmar Gabriel, Germany's economy minister, told Bild.
Gabriel suggested Europeans exhibit more self-confidence in dealing with Trump. "We're not weak and inferior," he said.
BMW said Monday that the company would stick to its plans to produce cars in Mexico.
"The production is aimed at the world market," BMW said, according to the German news agency dpa. "Therefore the plant in Mexico will complement ... the production plants in Germany and China."