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 Biden administration on Monday over its decision to block the merger of the two companies. The companies filed the lawsuit in the U.S. Court of Appeals for the District of Columbia,

Separate lawsuits from Nippon Steel and U.S. Steel target President Joe Biden as well as a steelworkers union head and a rival steelmaker’s CEO.