WHEELING — ArcelorMittal has sued Esmark Inc., the parent company of Wheeling-Pittsburgh Steel Corp., and a joint venture that was trying to buy a Maryland steel plant for $540 million, alleging breach of contract.

Esmark responded today that, although it has not received a copy of the lawsuit, it considers the action “frivolous.”

Meanwhile, Esmark’s filings with the Securities and Exchange Commission this week continue to tie the company to Essar of India.

Esmark had formed a joint venture called E2 in 2007 to mount a bid for ArcelorMittal’s Sparrows Point plant near Baltimore. Esmark intended to eventually merge the steel plant with Wheeling-Pittsburgh Steel Corp. and its steel service centers.

Esmark had been chosen by the U.S. Department of Justice as the bid winner for the Sparrows Point plant, which ArcelorMittal was selling to satisfy an antitrust decree.

However, Esmark’s $1.35 billion bid for the steel mill unraveled in December, shortly after Esmark completed its nearly two-year battle to merge with Wheeling-Pitt.

The Justice Department then put the Maryland plant out for bid again, with Russia’s Severstal the winner. Severstal and ArcelorMittal inked an $810 million cash deal that closed Wednesday.