FILE PHOTO: U.S. Under Secretary of State Andrea Thompson attends a panel discussion after a Treaty on the Non-Proliferation of Nuclear Weapons (NPT) conference in Beijing, China January 31, 2019. REUTERS/Thomas Peter/Pool

WASHINGTON (Reuters) - The U.S. under secretary of state for arms control and international security, Andrea Thompson, is leaving her post, Secretary of State Mike Pompeo said on Friday.

“Her wealth of knowledge, experience, and leadership skills will be missed,” Pompeo said in a statement.

Thompson submitted her resignation several days ago having decided that now was the right time to leave, said a person familiar with the matter. “She’s been in this administration since Day One,” said the person, who spoke on condition of anonymity.