SEOUL--An up-and-coming South Korean provincial governor announced his resignation on Tuesday, just hours after an aide accused him of repeated sexual assault, as the snowballing #MeToo movement rattled the country's political establishment.

The woman accused An Hee-jung, a leading hopeful in last year's presidential election and a member of President Moon Jae-in's Democratic Party, in a television interview on Monday evening. Police said were investigating the allegations.

An's office initially claimed that the sex was consensual; however, just a few hours after the interview was aired, An took to Facebook to say his staff’s statement was erroneous and announced he planned to resign and retire from political life.

"My staff office's description of the relationship as consensual was incorrect," he wrote. "Everything is my fault."

The Chungnam provincial police department said it has launched an investigation following the allegations.

Discussion of sexual misconduct has long been taboo in South Korea, but in recent months the anti-sexual harassment #MeToo movement has taken off, ensnaring a number of high-profile figures across various fields, from the entertainment industry to the religious community to the literary world.

Speaking to broadcaster JTBC, An's aide, Kim Ji-eun, said An had sexually harassed and repeatedly assaulted her.

"Over the past eight months I have been sexually assaulted four times," she told broadcaster JTBC.

"An recently talked to me about the growing sense of the #MeToo movement and it seems to me that he looked nervous and asked me if I was okay, then he said he was sorry," Kim said, adding that An nevertheless assaulted her again.

Both An and Kim were not immediately reachable for comment.

The ruling Democratic Party quickly moved to expel An from the party, with party head Choo Mi-ae saying that the alleged acts "should have never happened."

A youthful-looking 52-year-old, An became an unexpected challenger to Moon during last year's presidential primaries.

He was seen by many as a down-to-earth, uncomplicated politician, traits that served him well in a nation roiled by the impeachment of President Park Geun-hye in 2016.

Supporters nicknamed An the “EXO of South Chungcheong,” after a popular K-pop band, and his Instagram postings include a soap opera parody photo and a New Year video message featuring his cat.