A US news outlet has reported that President Joe Biden plans to formally block Nippon Steel's acquisition of US Steel.

US-based Bloomberg on Tuesday quoted sources familiar with the matter as saying that Biden will move against the deal. The US Committee on Foreign Investment will refer the case to his office by December 23.

White House Press Secretary Karine Jean-Pierre said on Tuesday that she doesn't have new information on the matter.

The Japanese steelmaker agreed with its US rival on the takeover a year ago. It is now being screened by the committee for national security issues.

Nippon Steel said in a comment responding to the Bloomberg report that partnership with the Japanese firm is the best path for US Steel to secure its future.

The Tokyo-based company also said that it is inappropriate for politics to outweigh true national interests.

The Japanese steelmaker says it still has confidence in the justice and fairness of America and its legal system.

It also said it will work with US Steel if necessary on all available measures to reach a fair conclusion.

Nippon Steel has been struggling to win approval as labor unions in the US steel industry are opposed to the deal.

The Japanese steelmaker announced on Wednesday it would give US Steel employees a one-time bonus of 5,000 dollars after the acquisition closes. The company says those payments will total about 100 million dollars.

Nippon Steel said its bonus offer addresses the concern of unions and government officials that rank-and-file employees often receive nothing for their contribution to the value a merger generates for stockholders.