South Korean President Park Geun-Hye personally apologised for an "unsavoury" incident during her US summit visit that led to the dismissal of her chief spokesman.
Yoon Chang-Jung was sacked over allegations that he had sexually harassed a female intern -- a Korean-American -- while accompanying Park on her May 5-9 trip.
"I feel apologetic that an unsavoury incident... occurred near the end of my visit to the US and greatly disappointed the people," Park told a meeting of senior aides on Monday.
"I sincerely apologise for the shock the female student and her parents must have received and the scars left on the hearts of (overseas) compatriots," she said, according to a report of the meeting posted on the presidential Blue House website.
The scandal has dominated press headlines in South Korea for several days, with reports pointing to major discrepancies in the various versions put forward and questioning the Blue House's initial reaction.
Park, South Korea's first woman leader, vowed that all the facts would be investigated so that no "single speck" of suspicion remained.
Washington police have opened an investigation into a complaint filed by the intern over a "misdemeanour sexual abuse" by an unnamed 56-year-old male suspect.
A Washington police report obtained by South Korean news agency Yonhap and The Washington Post said the intern complained the suspect "grabbed her buttocks without her permission".
Yoon, who flew back to South Korea before the end of Park's visit, denied the allegation on Saturday, saying he had merely "patted her waist" in a sign of encouragement.
"I implore her to forgive me if I had hurt her due to differences in culture. I offer my apology to her," he told reporters.
Park said all her officials would cooperate actively with the police investigation.
The affair cast a cloud over Park's US tour -- her first overseas trip since taking office in February.
Park held a summit with President Barack Obama, at which the two leaders reaffirmed their united front of offering no concessions in the face of provocations from North Korea.
She also addressed a joint session of the US Congress, stressing that Pyongyang had to give up its nuclear weapons.
North Korea was quick to pick up on the Yoon scandal, with the ruling party newspaper Rodong Sinmun crowing in a commentary Sunday that Park's US trip would be remembered for a "shameful" act of indecency.