The US Soccer Federation briefly displayed Iran's national flag on social media without the emblem of the Islamic Republic, saying the move supports protesters in Iran ahead of the two nations' World Cup match Tuesday in Qatar.

Iran's government reacted by accusing US Soccer of removing the name of God from their national flag, and the Iranian football federation says their country will lodge a complaint with FIFA over the scrubbing of the Islamic Republic emblem.

"Measures taken regarding the Islamic Republic of Iran flag are against international law and morality, and we'll pursue this through FIFA's morality committee. They must be held responsible," said legal adviser to the Iranian Football Federation Safia Allah Faghanpour.

"They must be held responsible. Obviously they want to affect Iran's performance against the US by doing this.''

The decision by the US Soccer Federation adds yet another political firestorm to the Middle East's first World Cup, one which organizers had hoped would be spared of off-the-field controversies.

It also comes as the US face Iran in a decisive World Cup match, which was already freighted by the decades of enmity between the two countries and the nationwide protests now challenging Tehran's theocratic government.

The USSF said in a statement Sunday morning that it decided to forgo the official flag on social media accounts to show "support for the women in Iran fighting for basic human rights.''

The Twitter account of the US men's team displayed a banner with the squad's matches in the group stage, with the Iranian flag bearing only its green, white and red colors. The same could be seen in a post on the team's Facebook and Instagram accounts laying out the point totals so far in its group.

By Sunday afternoon, the normal flag with the emblem had been restored in the Twitter banner as attention to it grew.

"We wanted to show our support for the women in Iran with our graphic for 24 hours,'' the federation said.

The USSF displayed the official Iranian flag in a graphic showing Group B standings on its website.

FIFA did not immediately respond to a request for comment on the dispute, according to The New York Times.

The brief absence of the emblem comes as months-long demonstrations have challenged Iran's government since the Sept. 16 death of 22-year-old Mahsa Amini, who had been detained by the country's morality police.

USMNT defenders Tim Ream and Walker Zimmerman said on Sunday that the players and coach Gregg Berhalter had no prior knowledge that the federation would be using their social channel to show support to the Iranian women's cause.

"I think it's such a focused group on the task at hand, but at the same time we empathize, and we are firm believers in women's rights and support them," Zimmerman said.

The protests have seen at least 450 people killed since they started, as well as over 18,000 arrested, according to Human Rights Activists in Iran, an advocacy group following the demonstrations.

Iran has not released casualty or arrest figures for months and alleges without providing evidence that the protests have been fomented by its enemies abroad, including the United States.

Tehran also restricts press access and has detained over 63 reporters and photographers since the demonstrations began, according to the Committee to Protect Journalists, making covering the unrest that much more difficult.

Iran's mission to the United Nations and its soccer federation did not respond to a request for comment from The Associated Press. As comments raged online, Iranian state television described the U.S. federation as "removing the symbol of Allah'' from the Iranian flag.

The Islamic Republic emblem, designed in 1980, is four curves with a sword between them. It represents the Islamic saying: "There is no god but God.'' It also resembles a tulip or lotus.

At the top and the bottom of the flag, there are 22 inscriptions of "God is Great" as well, which honors the date on the Persian calendar when the Islamic Revolution took hold.

The flag has become a point of contention at the World Cup. Apparent pro-government supporters have waved it, shouting at those demonstrating over Amini's death. Others at matches have waved Iran's lion and sun flag, an emblem of its former ruler, the late Shah Mohammad Reza Pahlavi.

More security forces could be seen at Iran's last match against Wales. In the capital Tehran, anti-riot police -- the same ones cracking down on protests -- waved the Iranian flag after the Wales win, angering demonstrators.