The federal judge said in a preliminary ruling that the National Treasury Employees Union likely must first bring their challenge to the Federal Labor Relations Authority.

Unions for federal workers have filed a lawsuit to block the mass firings of probationary federal employees by President Donald Trump’s administration, alleging that officials are exploiting and misusing the probationary period to eliminate staff across government agencies.

Several labor groups sued the Trump administration for allegedly firing tens of thousands of probationary employees illegally, as part of its drive to overhaul the federal government. In a complaint filed on Wednesday night in San Francisco federal court,