In her testimony, [Fiona] Hill described her fears that Mr. Sondland represented a counterintelligence risk because his actions made him vulnerable to foreign governments who could exploit his inexperience. She said Mr. Sondland extensively used a personal cellphone for official diplomatic business and repeatedly told foreign officials they were welcome to come to the White House whenever they liked.
Ms. Hill said that his invitations, which were highly unusual and not communicated to others at the White House, prompted one instance in which Romanian officials arrived at the White House without appointments, citing Mr. Sondland.