The presidential office Cheong Wa Dae offered a public apology Friday over allegations that the now-fired spokesman for President Park Geun-hye sexually assaulted a woman while accompanying Park on her first visit to Washington earlier this week.

 The swift apology underlines the seriousness of the case that sparked public outrage and dealt a blow to the image of the Park administration less than three months after its inauguration.

   "As senior press secretary, I am very disappointed and apologetic that a person belonging to my office was involved in an inappropriate act," senior presidential press secretary Lee Nam-ki said.

"I offer a heartfelt apology to the people and the president."

   The spokesman, Yoon Chang-jung, was accused of sexually assaulting a Korean-American woman in her early 20s at a hotel in Washington on Tuesday, just hours after Park held summit talks with U.S. President Barack Obama earlier in the day.

   Washington D.C. police said they are "investigating the report of a misdemeanor sexual abuse" by a 56-year-old male suspect. A police report said the suspect "grabbed her buttocks without her permission." It did not identify the suspect, but the age matches Yoon's.

   Park fired Yoon as soon as the case was made known.

   Yoon left Washington on Wednesday without accompanying Park to Los Angeles, the third and final stop of Park's five-day trip to the U.S.

   After arriving in Seoul on Thursday, he underwent questioning by the office of the senior presidential secretary for civil affairs.

   "What I can tell you for sure is that we reported the case to the president as soon as we determined what happened, and took an immediate measure. We will cooperate actively in the U.S.

investigation," Lee told reporters. "It is very regrettable that this kind of incident happened while the U.S. visit -- which was considered very successful -- was nearing its end, and I again deeply apologize to the people."