Iran were playing a friendly against Nigeria in the Mediterranean resort town of Belek on Friday ahead of the World Cup in the US, Mexico and Canada, with their participation in the tournament still in doubt due to the conflict.
The men lined up holding pink and purple bags with ribbons on them - a reference to the attack on the Shajareh Tayyebeh School that Tehran says killed more than 175 people, including children and teachers, on the first day of joint US-Israeli strikes on the country.
Mehdi Mohammad Nabi, a vice-president of the Iranian football federation, said the players had decided to stage the protest as a symbolic gesture of solidarity with the victims.
"They were deeply affected by the bombing of the girls' school and wanted to express their sympathy," Nabi said. "This was a collective decision by the team. We are united."
US military investigators believe it is likely that American forces were responsible but have not yet reached a final conclusion or completed their investigation.
The UN rights chief urged Washington on Friday to conclude its investigation into the strike at a meeting of the UN Human Rights Council.
Speaking in front of the stadium, Nabi said the team was aware of the discussions taking place at the rights council and hoped for a "clear and appropriate decision".
Earlier this month, some of Iran's women's soccer team stayed quiet during the national anthem at an Asian Cup match in Australia, leading state TV in Tehran to brand them "traitors".
President Donald Trump has said that while Iran were welcome to play in the World Cup in the US, it might not be appropriate for their "life and safety".
Iran's football federation said it was in discussions with soccer's world governing body FIFA about moving its World Cup matches to Mexico from the US.
The Iranians lost 2-1 to Nigeria and will play Costa Rica on Tuesday in another friendly in Turkey.
