The Hong Kong record-holder in the women's 100-meter hurdles, Lui Lai-yiu, said on Thursday that she had been sexually assaulted by her former coach 10 years ago, when she was 13 years old.

In a Facebook post, Lui said the coach offered her what he called a "physio treatment" and took her to his home, saying that the school's track was not a good place. He asked her to take her pants off because it was inconvenient for the treatment and then began to touch her private parts, she said.

Public reaction was swift. Hong Kong's Chief Executive Carrie Lam Cheng Yuet-ngor pledged on Thursday that the police will "seriously follow up" on the allegations.

She said she hoped Lui's disclosure of her experience will provide other sexual assault victims with the courage to speak up.

Lam added that she was saddened to hear the account but admired Lui's courage in telling her story.

The allegations by Lui were the first in Hong Kong's sports circles to be revealed to the public. The police said the case is now under investigation.

Secretary for Security John Lee Ka-chiu said that without the victim's assistance in providing more details, it would be difficult to deal with the case. He added that the police and other authorities would pursue the matter while protecting victims.

So far, there has been no other athlete-related sex crime reported to the police, he said. However, a lawmaker representing the Sports, Performing Arts, Culture and Publication sector, Ma Fung-kwok, said he received an anonymous report of a similar incident two weeks ago. He said he will respect the victim and investigate the case himself first. He condemned the sort of behavior attributed to Lui's former coach.

"Athletes devote themselves to winning, and their coaches are always the people they trust most. It is a shame if a coach takes advantage of an athlete's trust," Ma said.

Thursday was Lui's 23rd birthday. She said she believes there are similar cases in Hong Kong sports circles and encouraged other victims to come forward.

Her alma mater, Pui Ching Middle School, issued a statement condemning the coach and saying the school is saddened. Cheng King-leung, the school's vice-president who is in charge of sports, said the coach is an external lecturer and was suspended after the school received a private report from Lui two weeks ago.

The city's sports community expressed outrage. The Sports Federation and Olympic Committee of Hong Kong, China, issued a statement voicing sympathy for Lui and expressing admiration for the positive attitude she had shown.

The Hong Kong Amateur Athletic Association said that sexual assault not only breaks the trust between an athlete and coach but also causes irreparable damage to the athlete.

Lui's announcement came after United States' gymnast McKayla Maroney declared she had been sexually abused by the team's doctor since she was 13. Maroney posted her experience on Twitter on Oct 18.