WASHINGTON — The Trump administration’s chief of protocol in the State Department has been pulled off the job just ahead of the G-20 summit amid an investigation into allegations of discrimination and harassment, U.S. officials said. He is not expected to return to his job.

Two U.S. officials said that employees in the chief of protocol's office had been informed that Ambassador Sean Lawler had been suspended indefinitely pending the outcome of the investigation. A third official said that Lawler had told the State Department's leadership he planned to submit his resignation to President Donald Trump after the G-20 summit, which starts Friday in Osaka, Japan.

Lawler, a political appointee, was nominated by Trump to the position in September 2017 and given the rank of ambassador. He was confirmed by the Senate in November 2017.

Sean P. Lawler U.S. Department of State

Mary-Kate Fisher, the assistant chief of protocol, will attend the summit instead, the officials said.

The State Department declined to comment. An employee who answered the phone Tuesday in Lawler’s office said he was out of the office. Lawler declined to comment on the record.

The U.S. officials who told NBC News about Lawler’s situation declined to elaborate on the specifics of the allegations, other than to say that numerous employees in his office had resigned in protest of his management and behavior.

Among the behaviors that had caused concern, according to two U.S. officials, is that Lawler was known to carry a whip at work in what was perceived as an attempt to intimidate colleagues.

A senior position in U.S. diplomacy, the chief of protocol is responsible for ensuring diplomatic etiquette and overseeing the production of high-level diplomatic meetings, such as bilateral meetings with the U.S. president, vice president and secretary of state. As a result, the chief of protocol often attends important meetings overseas and interacts close-up with foreign leaders, including kings, queens and heads of state.

The suspension comes just as Trump prepares to fly to Osaka. The summit brings together leaders from 20 nations and is a Super Bowl of sorts for diplomats who work on protocol, which involves managing ceremonial details to help create “an environment for successful diplomacy,” according to the State Department’s website.

A regular participant in Trump’s foreign visits, Lawler was sworn in at the end of 2017, but has been in the U.S. government for almost three decades, according to his official State Department biography. His bio says he served more than 20 years in the Navy and also has worked in the White House’s National Security Council.