Major car-producing nations are due to meet without the U.S. to discuss possibly coordinating their response to President Donald Trump's threat of tariffs.

Representatives of the European Union, Canada, Mexico, South Korea and Japan will convene in Geneva on Tuesday to debate how to respond if the U.S. imposes levies on car imports, as well as prospects for reforming the World Trade Organization, according to three people familiar with the matter. Two officials said participants will explore the possibility of an international accord to cut tariffs on cars, although two other officials said this was not part of the formal agenda.

While European Commission President Jean-Claude Juncker and Trump agreed last week to refrain from "unilateral actions" as the EU and the U.S. negotiate a trade pact, a Commerce Department investigation under an act that permits the imposition trade restrictions if car imports are found to harm national security is still ongoing, keeping up the pressure on major exporting nations.