Secretary of State Rex Tillerson’s first trip abroad as secretary of state was to a G-20 meeting in Bonn, Germany. (Brendan Smialowski/AFP)

The State Department under Rex Tillerson, who has been among President Trump’s least visible Cabinet officials and is still lacking much of his senior staff, is undergoing further shrinkage in its upper echelons, according to current and former U.S. officials.

Kristie Kenney, a three-time ambassador and career Foreign Service officer who has served as State Department counselor for the past year, has been told that her services are no longer needed in that job and that her staff is to be reassigned. The offices of counselor, who provides strategic guidance to the secretary, and the empty slot of deputy secretary for management may not be filled, officials said.

Thomas Shannon, Kenney’s predecessor as counselor and now the undersecretary for political affairs, is expected to become acting deputy secretary for policy until someone is permanently approved.

Tillerson’s choice for the job, Elliot Abrams, was vetoed last week by the White House. Abrams, who served in the Reagan and George W. Bush administrations, subsequently speculated that he was blocked because of statements he made during the presidential race that were seen as critical of Trump’s candidacy.

The appointment of Tillerson, a former ExxonMobil executive with no previous government experience, was viewed favorably by much of the Republican establishment, which sees him as a steadying influence.

But since his arrival at the department on Feb. 2, he has made only one public comment, a brief statement Thursday at the G-20 conference of major world economic powers being held in Germany. He took no questions.

Five of the eight senior staff members who accompanied Tillerson on the trip — his first as America’s top diplomat — are serving in temporary capacities. Tillerson has not appointed a press secretary, and the State Department — which traditionally holds daily media briefings — has not held a single one.

Department officials said that Tillerson has described himself as being in a “listening mode” until he feels up to speed on the issues. His silence comes as the administration has become embroiled in controversy over contacts officials in the Trump campaign and transition had with Russian officials.

Although the secretary of state is traditionally included in virtually all formal presidential contacts with foreign leaders, Tillerson did not attend Trump’s meetings over the past week with Israeli Prime Minister Benjamin Netanyahu or Canadian Prime Minister Justin Trudeau.

Asked about the changes in the State Department’s seventh-floor executive suites, R.C. Hammond, who was press secretary for Newt Gingrich’s 2012 presidential campaign and currently is a department spokesperson, said in a statement that “the State Department is made up of a corps of very talented public servants. In some cases, we are redeploying people to new assignments where they can immediately put their talents to work.”

The removals and reassignments, some of which were first reported by CBS News, come as many senior jobs at State remain empty or filled by acting officials following the departure of those in charge of regional affairs and top issues such as nonproliferation and human rights. Most were career officials who were asked to leave, but there was also a handful who resigned.