(Reuters) -Esmark, a privately held company, said on Monday it had made an offer to buy U.S. Steel Corp for $35 per share, or an equity value of $7.8 billion.

On Sunday, U.S. Steel launched a formal review of strategic options, after rebuffing a takeover offer from rival steelmaker Cleveland-Cliffs.

The unsolicited cash-and-stock offer from Ohio-based Cleveland-Cliffs valued U.S. Steel at about $7.3 billion, representing a 43% premium to its closing price on Friday.

(Reporting by Ananta Agarwal and Ananya Mariam Rajesh in Bengaluru; Editing by Shounak Dasgupta)