Donald Trump said on Friday that any collective bargaining agreements reached with federal workers within 30 days of his inauguration will not be approved, the latest salvo in the president's bid to remake the federal workforce.

In a memo addressed to the heads of all executive departments and agencies, Trump said former President Joe Biden's administration purposefully finalized collective bargaining agreements with federal employees in its final days "in an effort to harm my administration by extending its wasteful and failing policies beyond its time in office."

It was not immediately clear how many agreements would be affected by the new policy, which refers to them as "lame-duck collective bargaining agreements."

Collective bargaining agreements are deals between unions and their employees that outline working conditions, pay, and other policies.

The move comes as Trump embarks on a massive makeover of the U.S. government, firing and sidelining hundreds of civil servants in his first steps toward downsizing the bureaucracy and installing more loyalists.

The memo cites a Department of Education collective bargaining agreement reached three days before Trump took office that "generally prohibits the agency from returning remote employees to their offices."

Trump has signed an executive order that would require federal employees to work in-office five days a week, reversing a remote working trend that took off in the early stages of the COVID-19 pandemic.