Iran has detained 35 women for trying to attend a football match.
They tried to go to a game between Tehran teams Esteqlal and Persepolis. Iran said they were temporarily held and would be released after the match.
Fifa's president, Gianni Infantino, was also in attendance, along with Iranian Sport Minister Masoud Soltanifar.
A live broadcast was taken off the air when a journalist asked Mr Soltanifar when women would be allowed to attend football matches.
According to the semi-official ISNA news agency, Iranian interior ministry spokesman Seyyed Salman Samani said the female football fans were not arrested - but transferred to a "proper place" by police.
Earlier reports said two women were held.
Iran has barred women from attending football games since the Iranian Revolution in 1979.
'Break the taboo'
There were calls on social media before the match for women to protest against the ban outside the Azadi stadium today.
Women's rights activist Masih Alinejad on Wednesday called on women to attend Thursday's match.
"The Fifa president will be in the stadium tomorrow (1 March)," she wrote.
"I wish women would gather outside the stadium to ask men not to enter without them."
Another user said it was a "basic right" for women to enter stadiums with men, and said this match was "the best chance to break the 35-year-old taboo".
Azadi means "freedom" stadium in Persian, and one Twitter user pointed out the hypocrisy of "naming a stadium freedom but banning half the population from entering".
Why this game?
By Alan Johnston, World Service Middle East regional editor
The women caught sneaking into the stadium were trying to attend a particularly significant game, one being watched by the most powerful man in world football, Fifa's boss.
It seems they wanted to attract Mr Infantino's attention to the ban on women attending games.
And the sensitivity of the issue was apparent as Mr Infantino stood beside the country's sports minister during a live TV interview.
A journalist asked this awkward question about when the ban might be lifted. The sound was faded down, and the interview abruptly taken off the air.
'Politics should stay out of football'
Mr Infantino had been speaking to reporters about a two-year dispute between Saudi Arabia and Iran.
Since 2016, when Saudi Arabia broke off relations with Iran, Saudi clubs have refused to play there, forcing Iranian teams to play home games in Oman.
"It's very clear that politics should stay out of football and football should stay out of politics," Mr Infantino said the news conference.
"There are of course political issues between countries all over the world but this should not have an impact," he said.
Later on, the head of Fifa met with Iranian President Hassan Rouhani.
Mr Rouhani asked Fifa to make sure that "people are not deprived of watching competitions in their own stadiums".