President Donald Trump announced he would double tariffs on steel imported to the U.S. from 25% of 50%, effective June 4.

The president said the change would "secure the steel industry in the United States," helping protect the jobs of domestic steel and aluminum workers.

President Trump announced the change during a speech at U.S. Steel’s Mon Valley Works–Irvin Plant in West Mifflin, Pennsylvania. He was attending to commemorate a deal in which Japan-based Nippon Steel is expected to make a new investment in U.S. Steel.

“The strong steel industry is not just a matter of dignity or prosperity or pride,” President Trump said. “It’s, above all, a matter of national security.”

The official details of the deal between Nippon Steel and U.S. Steel have not yet been announced. President Trump has said as part of the deal, Nippon Steel will invest $14 billion and U.S. Steel's headquarters will stay in Pittsburgh.

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The tariff escalation comes as courts have begun to weigh in on Trump's signature trade policies, this week pausing and then unpausing the sweeping tariffs Trump instituted on "Liberation Day" in April. Those rulings do not apply to the steel tariffs, which the White House has justified under separate national security laws.

Months of conflicting, escalating and backtracked tariff decisions from the White House have caused chaos and disruptions in shipping and business planning. Experts warn that it could take years and potentially cost billions of dollars to reshore manufacturing and supply chains to the U.S. Even if such a shift occurs, experts are skeptical about whether it would actually lead to job creation in America.