Republican front-runner and former U.S. President Donald Trump has said he would block Nippon Steel’s deal to buy United States Steel if he wins the November election, highlighting how his economic nationalism could imperil foreign investment in the U.S.

"I would block it instantaneously. Absolutely,” Trump said Wednesday after meeting with the members of the Teamsters union in Washington. "We saved the steel industry. Now, U.S. Steel is being bought by Japan. So terrible, but yeah, we want to bring jobs back to the country,” he added.

The comments marked Trump’s first public statement on the acquisition since the Japanese company announced in December it had agreed to buy the iconic American steelmaker for $14.1 billion.