Farsi-language media outside Iran warned that Elnaz Rekabi may have been forced to leave early by Iranian officials and could face arrest back home, which Tehran quickly denied.
The Instagram post on the account of Rekabi on Tuesday said: “I apologise about what I did to make you worry.”
The post also claimed that she was rushed at the competition although video of the event in Seoul showed her relaxed before she reached the climbing wall. The post described her as “unintentionally” not wearing her hijab.
The post also claimed that she was going back to Iran on a pre-arranged schedule.
Rekabi’s actions came as protests in Iran, sparked by the death in custody of a 22-year-old woman, have entered a fifth week.
Mahsa Amini was detained by the country’s morality police over her clothing.
The demonstrations, drawing school-age children, oil workers and others to the streets, represent the most serious challenge to Iran’s theocracy since the mass protests surrounding its disputed 2009 presidential election.
Rekabi left Seoul on a Tuesday morning flight, the Iranian Embassy in South Korea said.
The BBC’s Persian service, which has extensive contacts within Iran despite being banned from operating there, quoted an unnamed “informed source” who described Iranian officials as seizing both Rekabi’s mobile phone and passport.
BBC Persian also said she initially had been scheduled to return on Wednesday but her flight apparently had been moved unexpectedly.
IranWire, another website focusing on the country founded by Iranian-Canadian journalist Maziar Bahari who once was detained by Iran, alleged that Rekabi would be immediately transferred to Tehran’s notorious Evin Prison after arriving in the country.
Evin Prison was the site of a massive fire this weekend that killed at least eight prisoners.
In a tweet, the Iranian Embassy in Seoul denied “all the fake, false news and disinformation” regarding Rekabi’s departure on Tuesday.
But instead of posting a photo of her from the Seoul competition, it posted an image of her wearing a headscarf at a previous competition in Moscow, where she also took a bronze medal.
Rekabi did not put on a hijab during Sunday’s final at the International Federation of Sport Climbing’s Asia Championship, according to the Seoul-based Korea Alpine Federation, the organisers of the event.
Federation officials said Rekabi wore a hijab during her initial appearances at the one-week climbing event. Rekabi was a member of Iran’s 11-member delegation, which comprises of eight athletes and three coaches.
Federation officials said they were not initially aware of Rekabi competing without the hijab but looked into the case after receiving inquires about her.
They said the event does not have any rules on requiring female athletes wearing or not wearing headscarves. However, Iranian women competing abroad under the Iranian flag always wear the hijab.
South Korea’s Justice Ministry refused to confirm whether the Iranian athlete is still in South Korea or has left the country, citing privacy-related regulations.
Rekabi, 33, has finished on the podium three times in the Asian Championships, taking one silver and two bronze medals.