Feb 5 (Reuters) - United Steelworkers president David

McCall filed a motion to dismiss a lawsuit filed against him by

U.S. Steel and Nippon Steel ( NISTF ), the union said on

Wednesday.

The two steelmakers filed a lawsuit against McCall, rival

bidder Cleveland-Cliffs ( CLF ), its CEO Lourenco Goncalves last

month "for their illegal and coordinated actions" aimed at

preventing the $14.9 billion deal.

Former President Joe Biden had initially blocked the deal on

national security grounds in January, but delayed its

enforcement until June.

U.S. Steel's takeover by Japan's Nippon Steel ( NISTF ) had become

highly politicized ahead of the U.S. Presidential election in

November, with both Biden and Donald Trump vowing to terminate

it.

The deal also underwent a lengthy antitrust review by the

Committee on Foreign Investment in the United States (CFIUS)

under Biden's Presidency.

The companies also alleged Biden of unlawfully blocking the

deal in another lawsuit filed against his administration.

The deal, which was blocked on national security concerns,

had always faced opposition from the USW on grounds of lack of

transparency and job security risks, despite Nippon's multiple

attempts at assuaging their concerns.

The USW, however, has shown its support for Cliffs, which

was also reported to partner with peer Nucor ( NUE ) to prepare

a potential all-cash bid for U.S. Steel last month.

U.S. Steel and Nippon have alleged Cliffs, Goncalves and

McCall of colluding to allow Cliffs to "monopolize the domestic

steel markets" by thwarting any other attempts to buy the

123-year-old American steelmaker.

McCall filed the motion in the Western District of

Pennsylvania, with USW calling U.S. Steel and Nippon's lawsuit a

"frivolous and unsubstantiated attack" on the union for

exercising its first amendment rights.