The Commission said the U.S. action undermines ongoing efforts to reach a negotiated agreement.

BRUSSELS, May 31 (Xinhua) -- The European Commission (EC) on Saturday sharply criticized the United States' decision to raise tariffs on steel imports from 25 percent to 50 percent, warning that the move could prompt swift European retaliation.

"We strongly regret the announced increase," a Commission spokesperson said in an emailed statement, stating that the decision "adds further uncertainty to the global economy and increases costs for consumers and businesses on both sides of the Atlantic."

U.S. President Donald Trump announced Friday that he plans to double tariffs on steel and aluminum imports to 50 percent. In a post on his Truth Social platform, Trump said that the new rate would take effect on June 4.

The Commission said the U.S. action undermines ongoing efforts to reach a negotiated agreement. In April, the EU paused its own countermeasures to allow room for dialogue. However, it now signals a readiness to respond.

"The EU is prepared to impose countermeasures, including in response to the latest U.S. tariff increase," the spokesperson said, adding that the Commission is finalising consultations on expanded measures. Both existing and additional EU measures would take effect on July 14 -- or earlier -- "if circumstances require."

The Trump administration imposed sweeping 25 percent tariffs on all steel and aluminum imports on March 12, drawing sharp criticism from the U.S. auto industry. Canada responded with immediate retaliatory measures, while the European Union also announced counter-tariffs but ultimately withdrew them.

"The Commission has been clear about its readiness to act in defence of EU interests -- protecting our workers, consumers and industry," said the EC spokesperson.