TOKYO, Japan: After coming under public criticism for using Japanese Prime Minister Fumio Kishida's residence for a private party, his eldest son and executive secretary for political affairs, Shotaro Kishida, is set to resign.

Kishida invited a group, including relatives, to a year-end party on Dec. 30 at the Prime Minister's Official Residence.

Photos published by the weekly Shukan Bunshun magazine showed Kishida's son and relatives posing on red-carpeted stairs, in an imitation of the group photos taken of newly appointed Cabinets, with his son at the center - the position reserved for the prime minister. Other photos showed guests standing at a podium, as if conducting a news conference.

"As secretary for (the prime minister's) political affairs, a public position, his actions were inappropriate and I decided to replace him to have him take responsibility," Kishida told reporters Monday night. He said his son will be replaced with another secretary, Takayoshi Yamamoto, on Thursday.

Kishida acknowledged that he had briefly greeted the guests, but said he did not stay at the dinner party.

Although he said he severely reprimanded his son, Kishida failed to silence ongoing criticism from opposition lawmakers and public outrage.

It was not the first time Kishida's son has come under fire for making use of his official position for private activities. He was reprimanded for using embassy cars for private sightseeing in Britain and Paris, and for purchasing souvenirs for Cabinet members at a luxury department store in London when he accompanied his father on trips.