The European Commission president said it was the "duty of Europe" to stand up to US President Donald Trump if he decides to pull his country out of the Paris climate change accord.
Jean-Claude Juncker said on Wednesday "the Americans can't just get out of the agreement," adding "it takes three to four years" to pull out.
Juncker went on to say the Group of Seven leaders "tried to explain this in clear simple sentences to Mr Trump" at a recent summit in Italy. He said even though "it looks like that attempt failed" ... the "law is the law".
In a jibe at the US administration, Juncker told the audience at an event of the Confederation of German Employers in Berlin "not everything that is written in international agreements is fake news".
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