U.S. Steel and Japan’s Nippon Steel have filed a federal lawsuit challenging President Joe Biden’s decision last week to block a $14.9 billion merger between the two, the companies announced on Monday,

A first lawsuit was filed in the U.S. Court of Appeals for the District of Columbia Circuit, “challenging violation of the Constitutional guarantee of due process and statutory procedural requirements,” the companies said in a joint statement.

The suit, filed Monday 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.