U.S. President Donald Trump fired 17 independent watchdogs at multiple government agencies on Friday, a person with knowledge of the matter said, eliminating a critical oversight component and clearing the way to replace them with loyalists.

The inspectors general at agencies including the departments of state, defense and transportation were notified by emails from the White House personnel director that they had been terminated immediately, the source said on condition of anonymity.

The dismissals appeared to violate federal law, which requires the president to give both houses of Congress reasons for the dismissals 30 days in advance.