YOKOHAMA (Kyodo) -- Yokohama Mayor Takeharu Yamanaka admitted Friday to calling his subordinates and a city assembly member names such as "human scum" behind their backs, but pledged to exercise more self-control going forward.

The verbal abuse has drawn media scrutiny as the second-term mayor was publicly accused by a senior city official, first in a weekly magazine and then at a press conference, though he denied the allegation.

The mayor's problematic behavior was alleged by Atsushi Kubota, head of the city government's human resources department, who said he himself became a target of Yamanaka's verbal abuse.

Kubota told reporters Thursday that in June 2023, when he was the head of the city's international department, Yamanaka said to him, "If you fail to make Yokohama host TICAD, you must disembowel yourself."

TICAD stands for the Tokyo International Conference on African Development, a Japan-organized international meeting that connects Japan and African countries.

On another occasion, when the two were in the mayor's office, Yamanaka said, "If you betray me, you'll face this," gesturing to Kubota as if he were pointing a gun, aiming his index finger at him, according to Kubota.

The mayor also spoke ill of subordinates and a city assembly member when they were not around, describing them variously as "fat," a "useless sack of dust" and an "ostrich," according to the official.

Speaking to reporters on Friday, Yamanaka said he was "reflecting" on his behavior and will be "more careful with words and deeds."

To Kubota, the mayor said, "I want to apologize for making him suffer," adding that he intends to get professional help to correct his behavior.

Yamanaka denied making a threatening gesture toward him, however, and said his reference to forced suicide was an "expression of my resolve" to host the TICAD meeting.

After Yamanaka's apology, Kubota said, "Workers are not tools, and city assembly members are not enemies. I hope the mayor will understand the essence of matters and embrace it."

Kubota's accusations first appeared on Shukan Bunshun magazine's website on Jan. 11. The same day, Yamanaka denied the allegation in a statement on his website, claiming he did not speak ill of anyone for their appearance.

Yamanaka, 53, became Yokohama mayor in 2021, after serving as a professor in the School of Medicine at Yokohama City University. He was reelected last August.