The U.S. Department of Justice filed a motion last week to extend two deadlines in U.S. Steel and Nippon Steel's lawsuit against the Committee on Foreign Investment (CFIUS), a regulatory filing showed Monday.

The two companies in January jointly filed a lawsuit against CFIUS, which scrutinizes foreign investments for national security risks, after it recommended that a merger between the companies be rejected on national security grounds.

In the lawsuit against CFIUS, U.S. Steel and Nippon Steel have alleged that then U.S. President Joe Biden prejudiced the committee's decision and violated the companies' right to a fair review.

They claimed that Biden did so to win the favor of the United Steelworkers (USW) union in the swing state of Pennsylvania, where U.S. Steel is headquartered, in a bid for re-election.

The motion from the DoJ calls for extending briefing deadlines in the CFIUS lawsuit for 21 days, and rescheduling the oral argument to the week of May 12 from April 24.

The aim of the extension is to allow the government more time to complete its ongoing discussions with the steel companies on the merger, and eliminate the litigation against CFIUS, the filing by U.S. Steel showed.

In February, U.S. President Donald Trump said that he would not mind if Nippon Steel took a minority stake in U.S. Steel.

Following his comment, a Japanese government spokesperson said that Nippon Steel was considering proposing a bold change in its previous approach of seeking to buy U.S. Steel.

Nippon Steel also tried to schedule a meeting between Vice Chairman Takahiro Mori and U.S. Commerce Secretary Howard Lutnick, according to a report in February.

However, no deal has been inked yet.

U.S. Steel and Nippon Steel have consented to the motion, but it still remains subject to court approval.