Iran declined to sing their national anthem before their World Cup match with England in an apparent expression of support for anti-government protests in their home country.
Some fans shouted and jeered during the anthem and others held up signs saying "Woman, Life, Freedom".
Iran state TV cut its coverage of the anthem and switched to a previously shown wide shot of the stadium.
Mass protests have been met with a fierce crackdown in recent months.
They have been sparked by the death in custody in September of Mahsa Amini, a 22-year-old woman who was detained by morality police for allegedly breaking the strict rules around head coverings.
Human rights activists have said more than 400 protesters have been killed and 16,800 others arrested in a crackdown by Iran's security forces.
Iran's leaders say the protests are "riots" orchestrated by the country's foreign enemies.
Iranian fans could also be heard chanting "Ali Karimi" in the first-half in reference to the former footballer who is one of the most outspoken critics of the Islamic Republic and one of the most popular faces of the protest movement.
The fans could also be heard chanting "Be-Sharaf", which means dishonourable in Persian. This is an adjective that protesters have used against security forces in Iran.
Many opponents of the Islamic Republic have criticised the football team for not openly supporting the protests and for meeting with President Ebrahim Raisi last week.
Speaking before the game, Iran captain Ehsan Hajsafi said the players "support" those who have died.
Manager Carlos Queiroz has said his players were "free to protest" over women's rights in their home country as long as it "conforms with the World Cup regulations and is in the spirit of the game".
Iran's players also covered up their national team badge when they played two warm-up internationals in September.
