Merkel will host Trump and other G20 leaders at a July 7-8 summit that is shaping up to be a fractious meeting after he last month criticised NATO allies over their military spending and refused to endorse the global climate change accord.
Last month, Trump also tweeted: "We have a MASSIVE trade deficit with Germany, plus they pay FAR LESS than they should on NATO & military. Very bad for U.S. This will change".
He made those comments a day after Merkel ramped up her doubts about the reliability of Washington as an ally.
Merkel said it was important not to forget that George C. Marshall, the U.S. statesman after whom the Marshall Plan was named, "was convinced that good trade and a strong economy in Europe is good for American companies too".
"Protectionism, isolationism impedes innovation and in the long-run this is disadvantageous for everybody especially for those who count on isolationism even if they use different terminology for this," Merkel added, according an official translation into English of her remarks made in Germany.
