President Donald Trump's U.S. steel resurgence might be thwarted as more workers go on strike.

About 15,000 workers at plants owned by ArcelorMittal voted on Tuesday to go on strike as contract disputes drag on, USW International said.

"The flexibility of our contracts and world-class efficiency and productivity of this particular group of steelworkers enabled ArcelorMittal to survive floods of unfairly traded and illegally dumped foreign imports that brought about the harshest market conditions our industry has faced in decades," said Leo Gerard, president at USW International, in a statement.

"Now that the company is generating enormous — even historic — amounts of cash, it is an insult that bargaining progress has been hindered by management's unrealistic concessionary demands and unfair labor practices," Gerard said.

This follows another strike by 16,000 U.S. Steel workers that was approved earlier this month. Collectively, U.S. Steel and ArcelorMittal account for about 25 percent of the country's overall steel production. A strike this big could hinder what Trump calls a "thriving" industry in the U.S.

Trump tweeted on Monday that the U.S. steel industry is "is the talk of the World," adding it has been "given new life."

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Trump's tweet comes months after the U.S. slapped tariffs on all steel and aluminum imports, including those from key allies such as Canada, Mexico and the European Union.

The administration has said repeatedly that protecting the country's steel industry is a matter of national security. Trump said in a proclamation in May that "steel mill articles are being imported into the United States in such quantities and under such circumstances as to threaten to impair the national security of the United States."

Steel and aluminum producers initially cheered the administration's measures, but now workers want to reap some of the benefits.