The U.S. steelmaker said a federal interagency panel had granted an extension to June 18 for the requirement in President Biden’s executive order that the parties permanently abandon the transaction.

The Biden administration delayed until June an order for Nippon Steel to abandon its $14.9 billion bid for U.S. Steel , the companies said on Saturday, giving them some time to revive the politically contentious deal.

The suit, filed in the U.S. Court of Appeals for the District of Columbia, alleges that it was a political decision and violated the companies’ due process.

The Biden administration has given U.S. Steel and Japan’s Nippon Steel an extra six months to ditch their merger, keeping the deal alive as litigation unfolds over whether a national security panel’s review of it was tainted by political considerations.

The companies argued in a lawsuit announced on Monday that Biden violated the Constitution by blocking the merger via a sham national security review that deprived the companies of their right to a fair process.

US Steel and Nippon, whose $14.3 billion merger was blocked by President Joe Biden last week, filed a lawsuit against the US government Monday, claiming Biden’s executive order to bar the companies from combining was signed for “purely political reasons.

U.S. Steel and Japan’s Nippon Steel sued the United States government on Monday in a last-ditch attempt to revive their attempted merger after President Biden blocked it last week on the basis that the transaction posed a threat to national security.