With Iran still shaken by women-led protests over the death of Mahsa Amini one month ago, Elnaz Rekabi (33) flew back to a Tehran airport after the competition in South Korea.
In an Instagram post and comments at the airport, Rekabi has apologised over what happened and insisted her hijab - which all Iranian women including athletes must wear - had accidentally slipped off.
But activists fear her comments have been made under duress under pressure from the Iranian authorities who were likely infuriated by her actions.
"Elnaz is a hero," chanted dozens of supporters who gathered outside the Imam Khomeini International Airport terminal, clapping their hands and brandishing mobile phones to record the moment.
They continued to chant and applaud as a van and vehicle - one of which they presumed was carrying the climber - drive out of the airport through a sea of people clapping above their heads.
Some of the women present were not wearing the hijab themselves.
"A hero's welcome - including by women without the forced hijab - outside Tehran airport for-pro climber Elnaz Rekabi. Concerns for her safety remain," said the New York-based Center for Human Rights in Iran (CHRI).
'State propaganda'?
Rekabi, her hair covered with a baseball cap and a hoodie although not a headscarf, was greeted by family members inside the airport terminal. She then addressed state media, with a mask pulled down on her face.
"Due to the atmosphere prevailing in the finals of the competition and the unexpected call for me to start my run, I got tangled with my technical equipment and... that caused me to remain unaware of the hijab that I should have observed," she said.
"I returned to Iran peacefully, in perfect health and according to the predetermined plan. I apologise to the people of Iran because of the tensions created," she said, adding she had "no plan to say goodbye to the national team."
Her comments were similar to those made on Tuesday in an Instagram post, in which she apologised for "concerns" caused and insisted her bare-headed appearance had been "unintentional".
She was later photographed - still wearing a cap and hoodie - standing alongside Sports Minister Hamid Sajjadi, with whom she discussed "her future in sports and arranged plans, including participation and success in the Paris Olympics", a ministry statement said.
Activists have repeatedly accused the Islamic republic of coercing people into making statements of contrition on television or social media.
Observers "should not be swayed by state propaganda", said the CHRI.
Prominent exiled Iranian journalist Maziar Bahari described Rekabi's airport comments as a "forced confession".
"You can see the fear in her eyes. She's just repeating what she's been told," he said.
UN 'closely following'
Unconfirmed reports had already suggested she had been pressured by Iranian officials in South Korea.
BBC Persian quoted an unidentified source as saying friends had been unable to contact her and the team had left their hotel in Seoul on Monday, two days before their scheduled departure date.
News website Iran Wire said the head of Iran's climbing federation had "tricked" Rekabi into entering the Iranian embassy in Seoul. The federation chief had promised her safe passage to Iran if she handed over her phone and passport.
However, the Iranian embassy in Seoul issued a statement to AFP denying "all the fake, false news and disinformation regarding" Rekabi's situation.
The spokesperson for the UN office of the high commissioner for human rights, Ravina Shamdasani, said the UN was "closely following" the case and concerns were being raised with the Iranian authorities.
The incident took place at the Asian Championships in sports climbing in Seoul on Sunday.
In the initial bouldering discipline, Rekabi's head was covered with a bandana but in the later lead climbing, scaling a high wall with a rope, she wore only a headband, the stream posted by the International Federation of Sport Climbing (IFSC) showed.
The IFSC said in a statement that it had been in contact with Rekabi and the Iranian Climbing Federation and fully support "the rights of athletes, their choices, and expression of free speech".
