European Commission President Jean-Claude Juncker presents the EU's next long-term budget, at the European Parliament in Brussels, Belgium, May 2, 2018. REUTERS/Francois Lenoir

BRUSSELS (Reuters) - European Commission President Jean-Claude Juncker said on Wednesday the European Union will not accept threats in talks with the United States to secure a permanent exemption from U.S. import tariffs on steel and aluminum.

U.S. President Donald Trump has extended a temporary exemption for the European Union until June 1, although EU officials have said it is not clear what Washington wants.

“I would like to reiterate the call that this exemption be made unconditional and permanent. We consider that the U.S. measures cannot be justified on the basis of national security,” Juncker told the European Parliament.

“We will continue our negotiations with the United States, but we refuse to negotiate under threat,” Juncker said, while presenting the future EU budget plan.