Mr Juncker vowed European retaliation amid the growing threat of a full-scale trade war breaking out with the US. The European Commission president insisted that the US leader would be breaking a promise if he decided to implement tariffs on European cars. Eurocrats have already said Brussels would “react in a swift and adequate manner” if Mr Trump brands sales of European cars a threat to national security.
Washington’s trade department will issue a report this week after being asked to investigate the issue.
In a interview with German newspaper Stuttgarter Zeitung, Mr Juncker said he believes Mr Trump would keep “his word” and would not impose tariffs on European cars.
Mr Juncker said: “Donald Trump gave me his word that there won’t be any car tariffs for the time being. I believe him.
“Should he renege on that commitment, we will not longer feel bound by our commitments to buy more US soya and liquid gas. I would very much regret that.”
A spokesman for the European Commission said: “Were this report to translate into actions detrimental to European exports, the European Commission would react in a swift and adequate manner.”
Mr Trump has previously threatened tariffs of up to 25 percent on foreign-made cars, which would severely impact Germany’s prized industry.
Wilbur Ross, the US commerce secretary, on Sunday submit recommendations to the US President, who has 90 days to decide whether European cars pose a threat to national security and to act on the report.
German Chancellor Angela Merkel’s spokesman said: “From what we’ve heard, it does conclude that European car imports constitute a threat to US national security.”
He urged the Commission and Washington to resolve the issue through further negotiations, adding: “That is in our view the right way.”
Munich think thank boss Gabriel Felbermayr predicted German car exports to the US would be cut in half if 25 percent import tariffs were imposed.
The head of IFO’s centre for foreign trade said: “These tariffs would reduce total German car exports by 7.7 percent, or by €18.4bn.”
He added that 60 percent of the damage inflicted on the European car industry by any US tariffs would be felt by Germany.
On Saturday, Ms Merkel told the Munich Security Conference on Saturday many German cars sold in America are actually build in US factories.
“If such cars are suddenly a threat to US national security then I find that shocking,” she said.