President Donald Trump has ordered a new national security review of Nippon Steel’s proposed bid to buy U.S. Steel for nearly $15 billion.

Then-President Joe Biden blocked the deal just before leaving office and Trump had vowed to do the same in previous months. Late Monday, Trump ordered the Committee on Foreign Investment in the United States to review the transaction “to assist me in determining whether further action in this matter may be appropriate.”

The confidential review will look for potential national security risks from the proposed deal and the U.S. will give Nippon and U.S. Steel time to respond to any concerns.

The committee has 45 days to submit its recommendation. — Associated Press