Wearing the hijab is mandatory for female athletes from the Islamic Republic, but at the event in South Korea on Sunday Elnaz Rekabi did not wear one.

It follows a wave of protests in Iran over the past month which were sparked by the death of Mahsa Amini who was detained by the country's morality police over her clothing.

Since the 22-year-old's death, women in Iran have been removing their hijabs in public to make a stand.

The demonstrations represent the most serious challenge to Iran's theocracy since the mass protests surrounding its disputed 2009 presidential election.

After receiving a hero's welcome on her return to Iran on Wednesday, Ms Rekabi told a state TV reporter: "If I want to explain I should say that everything conforms to what I explained on the internet. It was completely unintentional. I think my (Instagram) story fully explained this.

"I was unexpectedly called and I had to compete. I was busy putting on my shoes and technical gear and that caused me to forget putting on the hijab I had to be wearing. Then I went to compete.

"Fortunately, I came back to Iran with peace of mind, although I went through a lot of tension and stress, so far, thank God, nothing has happened."

Told by the reporter about rumours that no one knew about her whereabouts for between 24 and 48 hours, Ms Rekabi replied: "No. This didn't happen. We came back to Iran according to the plan. Until this moment everything has been going on according to the plan."

An Instagram post on an account attributed to the athlete on Tuesday described her not wearing a hijab as accidental - though it was not clear whether she wrote it.

The Iranian government routinely pressures activists at home and abroad, often airing what rights groups describe as coerced confessions on state television.

The post that appeared on Instagram apologised for "getting everybody worried" and explained: "Because I was busy putting on my shoes and my gear, it caused me to forget to put on my hijab, and then I went to compete."

Video shared online appeared to show large crowds gathered early on Wednesday at Imam Khomeini International Airport outside of Tehran, the sanctioned nation's main gateway out of the country.

The 33-year-old athlete was seen walking into one of the airport's terminals, filmed by state television cameras, and wearing a black baseball cap and a black hoodie covering her hair. She received flowers from an onlooker.

Outside, she apparently entered a van and slowly was driven through the gathered crowd, who cheered her. It wasn't clear where she went after that.

A friend and former member of the national ice climbing team has said she is "very concerned" for Rekabi.

In a statement shared on Instagram, Zeinab Moosavi said: "Considering all the events that have happened, all of Iran and the world are worried about Elnaz's condition after her arrival in Iran."

'Interview must be treated with extreme caution'

Sky Sports News chief reporter Kaveh Solhekol says the interview Rekabi gave to Iranian state media must be treated with "extreme caution", as she may have been "under duress".

I think the first thing we have to say is, a lot of people will be saying that that interview was given under duress. I'm not sure if we were hearing exactly what Elnaz Rekabi really thinks about the situation she's in.

She was surrounded by people while she was giving that interview, she was escorted back to Iran, there have been reports that her family members have been arrested in Iran, so I think we have to treat with extreme caution what we've seen in that video.

In that video, the comments she was making, she was repeating what she said, apparently, on an Instagram post yesterday - saying that she was in a rush to compete and she forgot to put on her headscarf and it was a mistake.

That's one way of looking at it, that's the way the Islamic regime in Iran want you to look at it. Another way to look at it, which a lot of people will do, will be saying she made a very, very powerful statement, and she can't do anything more than that. She can't say anything more in public, she is in big, big danger.

When she arrived at Tehran airport this morning, there were hundreds of people there to greet her, hundreds of supporters who'd gone to the airport in the early hours because they knew she was being brought back to Iran, or flying back to Iran of her own free will, depending on who you want to believe.

Those people who were at the airport were chanting her name in Persian, they were chanting Elnaz is a hero, so they seem to be supporting the protest that she had made.