The main opposition Democratic Part(DP) urged President Park Geun-hye Friday to publicly apologize over allegations that her spokesman had sexually assaulted a young woman in the United States earlier this week.

The allegations emerged after Park's office announced earlier in the day that the president had fired her spokesman, Yoon Chang-jung, during her five-day official visit to the U.S. this week.

Yoon is suspected of sexually harassing a Korean woman in her early 20s at a hotel in Washington on Tuesday. The woman was temporarily hired by the Korean embassy there to assist with duties related to the president's visit.

Police in Washington have launched an investigation into the allegations. The presidential office cited an unspecified "unsavory" act as the reason for the sacking.

"President Park and Cheong Wa Dae should deeply reflect on their appointment of the wrong personnel and apologize to the people," Rep. Kim Kwan-young, the DP's senior spokesman, said. Cheong Wa Dae is the name of South Korea's presidential office.

"There must be a thorough investigation into (the allegations) that damaged our country's dignity and caused national shame," he said, adding that those responsible should be held accountable.

Calling the incident a "foreseeable tragedy," Kim also blamed the president for appointing Yoon despite widespread criticism that the former political columnist was unfit for the job due to his biased and sensational views.

Park, who took office in late February, came under fire during the early weeks of her term when a number of her nominees for senior government posts resigned in succession under pressure over allegations of ethical lapses and other problems.

Meanwhile, the ruling Saenuri Party expressed "regret" over the case and called for a thorough investigation.

"A thorough investigation should be conducted to find the truth," said Saenuri spokeswoman Rep. Min Hyun-joo. "I hope that the mistake of one individual does not cloud all the achievements of President Park's visit to the United States."

Park, who is scheduled to arrive home later in the day, held summit talks with U.S. President Barack Obama at the White House on Tuesday. (Yonhap News)