TOKYO, Sept 13 Reuters Nippon Steel and U.S. Steel sent a letter on Sunday to U.S. President Joe Biden about their planned 15 billion merger after media reported that he was preparing to block the deal, a spokesperson for the Japanese steelmaker said.

The spokesperson did not provide details about the letter39;s content, but said it was signed by Nippon Steel Chief Executive Eiji Hashimoto and U.S. Steel CEO David Burritt as well as other executives.

U.S. Steel did not immediately respond to a request for comment outside of U.S. business hours. The U.S. embassy in Japan did not immediately have comment.

Japan39;s biggest steelmaker is pursuing a cash deal to buy the 123yearold U.S. Steel, despite resistance from Biden, the United Steel Workers USW union and many members of Congress while a U.S. national security review is conducted.

The deal has also been opposed by both Republican presidential nominee Donald Trump and Democratic nominee Kamala Harris. Both are vying to win the critical swing state of Pennsylvania, where U.S. Steel is headquartered.

The Committee on Foreign Investment in the United States CFIUS told the companies in an Aug. 31 letter seen by Reuters the deal would create national security risks because it could hurt the supply of steel needed for critical transportation, infrastructure, construction and agriculture projects.

A top Nippon Steel executive and U.S. Steel39;s CEO met with senior U.S. officials on Wednesday in an effort to salvage the…