Trump, who is known to have a strong protectionist bent on trade, has said the United States will impose tariffs on European car imports if it is unable to reach a trade deal with the European Union.
European Commission President Jean-Claude Juncker said in July that Trump promised he would hold off for the time being while the two sides sought to improve trade relations, such as with a deal to cut tariffs on â€śnon-auto industrial goodsâ€ť.
A confidential report by the U.S. Commerce Department sent to Trump last weekend was expected to pave the way for the U.S. president to impose duties of up to 25 percent on imported autos and auto parts by designating them as a threat to U.S. national security.
The European Commission, which coordinates trade policy for the 28-member EU, has said it is preparing a list of U.S. products to target with tariffs should Trump decide EU car imports need to be restricted.
The Commission told national ministers at a meeting about trade in Bucharest that its list was ready, EU diplomats said, although it did not disclose what was in it.
It would go after 20 billion euros ($22.7 billion) worth of U.S. imports, although the list would take the form of categories of products, rather than specific companies.
EU car and car parts exports to the United States are worth around 50 billion euros per year, with the bulk of them coming from Germany.
The EU has already imposed its own import tariffs on 2.8 billion euros worth of U.S. products ranging from bourbon to motor-bikes as a response to U.S. punitive duties on EU steel and aluminium imports, which had been worth 6.4 billion euros.
â€śShould there be tariffs on cars and car parts, we donâ€™t know, but if it happens we have started internally to prepare a list of rebalancing measures,â€ť EU Trade Commissioner Cecilia Malmstrom told a news conference in Bucharest.
â€śThere is full support to do this. Of course if it happens we would immediately publish that list for formal consultation,â€ť she continuing, adding that U.S. car tariffs would also lead to the end of planned trade negotiations with Washington.
Xerox, Caterpillar and Samsonite did not immediately respond to requests for comment.
($1 = 0.8819 euros)