President Donald Trump's plan to impose tariffs on steel and aluminum imports would make Exxon Mobil Corp. (XOM)   less competitive and erase some of the positive effects the Trump administration has achieved with deregulation and cutting U.S. corporate taxes, Exxon Chairman and CEO Darren Woods said today.

The Irving, Texas-based supermajor oil company announced last March a $20 billion investment to expand manufacturing in the U.S. Gulf Region. Following the passage of the new U.S. tax legislation in December, Woods said Exxon would invest more than $50 billion in the U.S. over the next five years.

But the president is looking to implement a 25% tariff on imported steel and a 10% tariff on aluminum imports. Trump is arguing that the tariffs will help protect and build up the steel and aluminum industries in the U.S. Beyond that, details are limited. It is unclear if the plan will exempt certain countries, such as Mexico and Canada. There are also conflicting reports about when and if the president will make the announcement this week.

"I think the talk of the tariff is still yet to be defined; it actually takes us back the opposite direction and makes the investments less competitive," Woods said on CNBC Thursday morning.

Still, Woods said there are no plans to change the company's capital expenditure outlook.

Shares of Exxon rose 0.3%% to $74.47 at 10 a.m. EST.

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