A female Iranian activist who held a protest banner during a volleyball match at the Rio Olympics was asked to take it down and leave by security staff.
Darya Safai's sign read: "Let Iranian women enter their stadiums."
Women have generally been banned or restricted from attending all-male sports events in Iran since shortly after the Islamic revolution in 1979.
The International Olympic Committee bans political statements at the games.
After she refused to leave, security staff abandoned their attempt to remove her and she carried on holding up the banner for the rest of the game.
Ms Safai says she plans to attend all of Iran's volleyball matches. The next one is on Monday.
Ms Safai, who was born in Iran but lives in Belgium, held her protest on Saturday at a men's preliminary volleyball match between Egypt and Iran.
Although she seemed to smile throughout that protest, Ms Safai did at one point burst into tears when security staff came to try to remove her.
She said to them: "I am so sorry. What I am fighting for is for the right for Iranian women to be at matches. It is my right to be here. It is the basic right of Iranian women."
She said she cried because "it hurts to explain again and again that this peaceful action is not a political message, but a positive message of peace and human rights".
"I kept the banner up for the whole length of the match," she told the BBC News website. "My hands were shivering from holding the banner. But I kept it until the end."
Not everyone was supportive - one Iranian fan sitting behind her at the match yelled at her, she said.
Ms Safai, has lived in Belgium since 2000, after being arrested in Iran in 1999 and put in prison for taking part in anti-government demonstrations.
She has been staging sports protests since 2014.
"I love volleyball, football, because I love our national team. We want to enjoy [the team], men and women. I want to cheer my national team, it is my right and that of all Iranian women whose voice is muted.
"Where better than the Olympic Games to bring people together?"
She says her protest is "to let the Olympic committee know that they have an important mission to let Iranian women enter the stadiums".
"They have a lot of power in the world of sports and I hope they will use it to fight gender discrimination. That's what the spirit of the Olympic Games is," she said.
Since 2012, the Iranian government has banned women from attending volleyball tournaments as the sport became increasingly popular in Iran with both sexes.
It has arrested women for trying to enter stadiums, human rights groups say.