Some fans were stopped by stadium security from bringing in Persian pre-revolutionary flags to a match against Wales at the Ahmad Bin Ali Stadium.
Others carrying such flags had them ripped from their hands by pro-government Iran fans, who also shouted insults at fans wearing T-shirts with the slogan of the protest movement gripping the country, ``Woman, Life, Freedom.''
Unlike in their first match against England, the Iran players sang along to their national anthem before the match as some fans in the stadium wept, whistled and booed.
The national team has come under close scrutiny for any statements or gestures about the nationwide protests that have wracked Iran for weeks.
Shouting matches erupted in lines outside the stadium between fans screaming ``Women, Life, Freedom'' and others shouting back ``The Islamic Republic!''
Small mobs of men surrounded three different women giving interviews about the protests to foreign media outside the stadium, disrupting broadcasts as they angrily chanted, ``The Islamic Republic of Iran!'' Many female fans appeared shaken as Iranian government supporters shouted at them in Farsi and filmed them close-up on their phones.
One 35-year-old woman named Maryam, who like other Iran fans declined to give her last name for fear of government reprisals, started to cry as shouting men blowing horns encircled her and filmed her face. She had the words ``Woman Life Freedom'' painted on her face.
``We want to raise awareness about his arrest and about the women's rights movement. Simple,'' said Maryam, who lives in London but is originally from Tehran. ``I'm not here to fight with anyone, but people have been attacking me and calling me a terrorist. All I'm here to say is that football doesn't matter if people are getting killed in the streets.''
Maryam and her friends had worn hats emblazoned with the name of an outspoken Iranian former soccer player Voria Ghafouri, who had criticized Iranian authorities and was arrested in Iran on Thursday on accusations of spreading propaganda against the government.
She said Iranian government supporters had taken the hats from their heads.
Ghafouri, who is Kurdish, was a star member of Iran's 2018 World Cup team, but was surprisingly not named in the squad for this year in Qatar.
``It's obvious that the match had become very politicized this week. You can see people from the same country who hate each other,'' said Mustafa, a 40-year-old Iran fan who also declined to give his surname. ``I think the arrest of Voria has also affected society in Iran a lot.''
Furious protesters in Iran have been venting their anger over social and political repression and the state-mandated headscarf, or hijab, for women.
The demonstrations, spurred by the Sept. 16 death of 22-year-old Mahsa Amini in the custody of the country's morality police, have quickly grown into calls for the downfall of the Islamic Republic itself. At least 419 people have been killed since the protests erupted, according to the monitoring group Human Rights Activists in Iran.
The turmoil has overshadowed the start of Iran's World Cup campaign. The opening match against England on Monday was the scene of protests as anti-government fans waved signs and chanted in the stands.
Before that match, when Iran lost 6-2, its players remained silent as their national anthem played and didn't celebrate their two goals. On Friday they sang along to the anthem and celebrated wildly when they scored in the 2-0 win against Wales.
Ayeh Shams from the United States, who was at the game against Wales with her brother, said security guards confiscated her flag because it had the word ``women'' on it.
``We're first-generation Americans. Our parents were born in Iran. We're just here to enjoy the games and give a platform for the Iranian people who are fighting against the Islamic regime,'' Shams said.
Zeinlabda Arwa, a security guard at the stadium, confirmed that authorities had been given orders to confiscate anything but the flag of the Islamic Republic of Iran.
``Whether you're talking about Iran or Qatar or any country, you are only allowed to bring in the normal flag,'' she said.
An angry group of Iranian government supporters shouted at Elyas Doerr, a 16-year-old Iranian living in Arizona who was wearing the Persian flag as a cape, until he took it off and and put it in his bag.
``They're not liking that it's a political statement,'' he said, adding that other Iranian fans had approached him to say they appreciated the gesture.
Before Friday's match, Iranians chanted anti-government slogans from rooftops in Tehran. Scattered protests also erupted in Kurdish towns in the country's west and across the central city of Isfahan on Thursday.
Iranian state TV on Friday devoted its main news bulletin to Iranians' soccer prowess, wishing the national team luck against Wales and airing a montage of Iranian goals throughout history.