Officials with the European Union say it looks increasingly unlikely that they will be able to reach an agreement with the White House to permanently exempt the 28-nation bloc from the steel tariffs the U.S. put in place in March.

Shortly after President Donald Trump announced the tariffs on imports of steel and aluminum, he exempted several allies, including the Canada, Mexico and the EU, while negotiating for new trade agreements. The EU’s exemption is due to expire June 1.

After the tariffs were announced, the EU released a list of American products, including HVAC equipment, it was ready to hit with taxes equal to the 25 percent tariff the U.S. was imposing on steel imports. The move was dropped when the EU was granted a temporary exemption. The EU will likely institute the retaliatory tariffs next month, observers say.

European Commission President Jean-Claude Juncker has said the EU will not be bullied.

"We strongly regret this step, which appears to represent a blatant intervention to protect US domestic industry,” Junker said in a March statement. “Protectionism cannot be the answer to our common problem in the steel sector. Instead of providing a solution, this move can only aggravate matters. The EU has been a close security ally of the U.S. for decades. We will not sit idly while our industry is hit with unfair measures that put thousands of European jobs at risk.”

News reports Thursday said Trump was considering using the same law he cited to enact the steel tariffs as rationale to put a similar tax on cars imported from overseas. About 44 percent of vehicles sold last year in the U.S. were imported.