A State Department political appointee has been vetting career employees for their loyalty to President Trump, leading at least three to quit, according to a report in Foreign Policy.

Mari Stull, a senior advisor to the Bureau of International Organization Affairs (BIOA), is alleged to be combing the social media pages of diplomats and other State Department and UN workers looking for indications of their political views, investigating their work under previous administrations, and compiling lists of people she believes are not loyal to the Trump administration. Those viewed as suspicious have been excluded from meetings and briefings.

“This conduct is totally unacceptable, and adds to my concern about the treatment of career personnel by this Administration,” Rep. Eliot Engel (D-NY), the top Democrat on the House committee that oversees the State Department, told TPM. “I’ll be looking into this, and I won’t stand for any more stonewalling from the State Department,” he added, referring to the agency’s unmet promise to turn over documents to Congress about alleged retaliation against career workers.

Stull, a former food and beverage lobbyist who also blogged about wine under the pen name Vino Vixen, was hired in April to work with BIOA, the State Department office in charge of diplomatic relations with the United Nations and other international bodies.

Foreign Policy reports that Stoll’s practices have driven at least three senior career officials to quit the bureau. “I have in my entire federal career never experienced anything at this level of chaos and dysfunction,” one source told the magazine.

A State Department spokesperson told Foreign Policy in response to the report: “Political retribution of any kind will not be tolerated and we take these allegations very seriously.” The spokesperson added that Secretary of State Mike Pompeo “has shown his full support for career staff at the State Department and at the Central Intelligence Agency.”

The targeting of non-partisan, career federal workers based on their perceived political loyalties has been a key feature of the Trump administration and of the State Department in particular. Under former Secretary of State Rex Tillerson, who was fired by Trump in March, political appointees worked to sideline career employees who had worked on Obama administration priorities like the Iran nuclear deal, the closure of the Guantanamo Bay prison, and the resettlement of refugees. Many of them were forced out of their roles and reassigned to low-level work processing Freedom of Information Act requests.

Under Pompeo, the “FOIA surge” has ended. But State Department sources and members of Congress tell TPM they remain concerned about the administration’s attempts to politicize the career civilian workforce, and the allegations have trigged ongoing internal investigations.