Elon Musk caused alarm among federal employees and drew ire over an email sent on Saturday requesting that employees summarize their work for the week, and warning on social media that a failure to do so would be taken as a resignation.

Attorneys for federal workers said Monday in a lawsuit that billionaire Trump adviser Elon Musk had violated the law with his weekend demand that employees explain their accomplishments or risk being fired.

Multiple major agencies, including the FBI, State Department and Pentagon, have directed employees not to respond to Musk’s email.