(CNN) President Donald Trump's protocol chief, Sean Lawler, has been suspended indefinitely just ahead of the G-20 meeting in Japan pending the outcome of a State Department investigation into his conduct, according to multiple State Department officials with direct knowledge of the matter.

Two State officials told CNN that Lawler was called into the office of the deputy secretary on Monday afternoon and told he needed to leave due to the status of the investigation.

On the same afternoon, senior staff in the protocol office met with State Department management and were told that Lawler had to leave over personnel issues, according to the officials.

They were also told in this meeting that their new acting chief of protocol is Mary-Kate Fisher, and her acting deputy is Cathy Fenton, who served as social secretary in the George W. Bush White House and also handled social affairs‎ for Nancy Reagan and Barbara Bush. State Department sources said both are highly respected.

One of the State Department officials described what multiple others told CNN was a pattern of behavior on Lawler's part. "In my decade of government service, I have never seen someone so unprofessional, abrasive and rude as him," the official said. "His bad behavior was terrible, and it was obvious. I personally saw it myself, as did a good chunk of the office.

"For example, in a recent meeting -- a very routine planning meeting -- when he asked a question, if he didn't like the answer, he would immediately raise his voice, get angry, start using profanity, and use the 'F word.'

"Then, a moment later, like the flip of a switch, he'd calm himself down and it would be like nothing happened. This has happened before. Many times. And everyone would talk about it after. Their reaction was, 'What the hell just happened? Did he just start screaming at someone younger, or a woman, or an African American, in an extremely derogatory, condescending fashion? Did he just use the 'F word' several times? Did that really just happen?'"

Bloomberg was first to report that Lawler's conduct was being investigated.

"A large chunk of the protocol office was aware of this behavior for a long time. They're surprised, to be honest, that this hadn't been dealt with sooner," according to the State Department official. "It's stressful enough, just trying to get work product done."

"His behavior made itself clear not just around the office—but on trips with the President, in bilats, and engagements with the White House," the official added.

Lawler has been in office more than 18 months. He did not respond to multiple requests by CNN for comment.

Neither the White House nor the State Department has officially commented.