Seoul, South Korea (CNN) -- President Park Geun-hye of South Korea has dismissed her press spokesman after concluding that he was involved in an "unsavory incident" during a state visit to the United States, her office said.

Police in Washington said they were investigating a report of sexual abuse.

The spokesman, Yoon Chang-jung, "showed inappropriate conduct as a high-ranking official and damaged the dignity of the country by being personally involved in an unsavory incident," the chief presidential press secretary, Lee Nam-ki, said in a statement Thursday from Los Angeles.

The embarrassing affair adds an awkward coda to the five-day visit to the United States by Park, South Korea's first female president. During the high-profile trip, her first since taking office in February, she met with President Barack Obama to discuss the recent tensions with North Korea along with other strategic and economic issues.

The South Korean Embassy in Washington now is investigating the incident, Lee said without providing further details on what Yoon is alleged to have done. The presidential office in Seoul didn't respond to repeated requests for further comment.

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Asked about the matter, Gwendolyn Crump, a spokeswoman for the Metropolitan Police Department in Washington, said, "We are investigating the report of a misdemeanor sexual abuse. We cannot comment further, at this time."

In South Korea, the Democratic Party, the leading opposition group, called for Park to publicly apologize over the matter on Friday, the semiofficial news agency Yonhap reported.

Park and her office "should deeply reflect on their appointment of the wrong personnel and apologize to the people," said Kim Kwan-young, the party's senior spokesman, according to Yonhap.

Park is due to arrive back in Seoul on Friday evening.

Journalist Soo Bin Park reported from Seoul, and CNN's Jethro Mullen reported and wrote from Hong Kong. CNN's Alison Harding in Washington and Judy Kwon in Hong Kong contributed to this report.