Japan's Nippon Steel is committed to its $15 billion acquisition of U.S. Steel and is confident of completing it by year-end, a senior executive said, despite strong U.S. opposition including from President-elect Donald Trump.

Almost a year after Nippon Steel announced its takeover plan, hefty political hurdles remain. President-elect Donald Trump this week repeated his opposition to the sale of U.S. Steel, saying he’d instead use tariffs and tax incentives to revitalize the American steelmaker.

U.S. Steel has warned that without the Nippon Steel investment, it could close mills and move its headquarters from Pittsburgh.

"I'm on the side of making steel. I'm on the side for making steel for whoever owns this facility," said worker Jesse Smith. "I'm partial towards it being domestic and individuals

This April 26, 2010, shows the United States Steel logo outside the headquarters building in downtown Pittsburgh. President-elect Donald Trump is underscoring his intention to block the purchase of U.

Donald Trump reiterated his opposition to the sale of United States Steel Corp. to Nippon Steel Corp., saying he’d instead use tariffs and tax incentives to revive the American steelmaker.

The announcement reiterated sentiments the president-elect expressed on the campaign trail, and further imperiled a deal that had already run into widespread political opposition.