President-elect Donald Trump reaffirmed his opposition to Japanese-owned Nippon Steel acquiring U.S. Steel in a Truth Social post made on Monday.

“I am totally against the once great and powerful U.S. Steel being bought by a foreign company, in this case Nippon Steel of Japan,” Trump wrote. “Through a series of Tax Incentives and Tariffs, we will make U.S. Steel Strong and Great Again, and it will happen FAST! As President, I will block this deal from happening. Buyer Beware!!!”