President Donald Trump said South Korea plans to invest about $54 billion in a natural gas project in Alaska, an announcement he made in the Oval Office on Wednesday flanked by a Republican senator who has found himself in a tough reelection race in the state.

But while Trump and Alaska Sen. Dan Sullivan — a two-term senator and long-time advocate for the pipeline project — described it as a fait accompli, South Korean officials were more cautious, saying they needed to assess the project's commercial viability before committing to the investment.