An asset manager is seeking to quash Nippon Steel’s takeover of U.S. Steel and oust the leadership of the U.S. steelmaker after taking a stake in the company.

United States Steel Corp. said Sunday that it rejected a $7.3 billion buyout proposal from rival Cleveland Cliffs and was reviewing “strategic alternatives” after receiving several unsolicited offers.

The steelmarker reported its first loss since early 2017, about a year before the Trump administration imposed 25% tariffs on steel imports in 2018. Those tariffs were designed to help reduce competition for the domestic steel industry and allow companies to add jobs and production. The tariffs did give steel prices a brief spike and prompted some steel companies, including US Steel, to bring shuttered American mills back on line. But the increased production, along with a drop in demand from steel customers, resulted in prices falling back. And late Thursday it reported an operating loss of $35 million in the quarter.