U.S. Ambassador to Greece Kimberly Guilfoyle announced her resignation on Tuesday after the White House asked her to leave her post amid allegations of improper conduct.

The decision followed reports that President Donald Trump and Secretary of State Marco Rubio were dissatisfied with allegations concerning her behavior before and during her tenure in Athens.

White House press secretary Katie Zacharia described Guilfoyle as a valuable member of the team and wished her well during her first media briefing.

Trump said the administration had become concerned by reports about Guilfoyle’s alleged conduct, adding that she would no longer serve as ambassador, NPR has reported.

Guilfoyle said she would vigorously defend herself, while the allegations and circumstances surrounding her departure drew increased scrutiny.