The United States and Iran will face off Tuesday as part of the 2022 FIFA World Cup.

Controversy, however, began before the match after the U.S. Soccer Federation temporarily posted a photo of the nation’s flag without the symbol in the center.

Iran has seen mass protesting since the death of Mahsa Amini in September.

Vexillologist Michael Green, founder of Flags for Good and member of the North American Vexillogical Association, joined Spectrum News to discuss the flag’s significance.

A vexillologist is someone who studies flag.