Dozens of Iran supporters at the World Cup defied FIFA’s ban by displaying the pre-revolutionary Iranian flag inside SoFi Stadium — giving the soccer org’s ruling a big middle finger.

Ahead of Iran’s World Cup opener against New Zealand on Monday, hundreds of demonstrators rallied outside the stadium to protest the Iranian regime. Inside SoFi Stadium, the pre-revolutionary Iranian flag was visible throughout the crowd, with fans displaying it on flags and T-shirts alike.

FIFA said the pre-revolutionary flag violated the org’s code of conduct, which states “banners, flags, fliers, apparel and other paraphernalia, that are of a political, offensive and/or discriminatory nature” will not be allowed at event venues in a decision back in May.

Security at SoFi Stadium was tight, with fans passing through metal detectors and bag checks. The Post observed security asking one group of fans to remove T-shirts featuring the pre-revolutionary Iranian flag. After the fans said they had no other clothing, security instructed them to turn the shirts inside out. But once inside the stadium, little appeared to be enforced, with the flags and T-shirts visible throughout the stands.

Some Iranian fans also turned their backs to the field when the national anthem was played.

Large crowds waving Iranian flags and wearing red, white and green as they voiced opposition to the Islamic Republic all gathered outside the stadium before kickoff. Some chanted “USA” while others displayed photos of athletes who had been killed by the regime.

Los Angeles is home to the nation’s largest Iranian community, with an estimated 600,000 Persian Americans concentrated around Westwood Boulevard, often dubbed “Tehrangeles.”

Supporters of the National Council of Resistance of Iran first gathered around SoFi Stadium at about 11 a.m. Monday.

Organizers said the demonstration aimed to underscore what they described as the contrast between the Iranian regime’s international image and its treatment of dissidents at home.

The rally also worked to spotlight allegations that the Islamic Revolutionary Guard Corps (IRGC) exerts significant control over Iran’s sports federations and suppresses athletes who express dissent or engage in protest.

The Iranian team landed in the U.S. on Sunday – just one day before the match – due to visa complications that several senior officials from the Iranian football federation faced over alleged links to the Iranian regime.

The team stayed at Westdrift Manhattan Beach, a four-star hotel roughly six miles from SoFi Stadium.

The hotel was heavily fortified, with layers of security and entrance and exit points heavily sealed off to only hotel guests.

Pre-revolutionary Iran flags have also been banned from stadiums as FIFA rules states that “banners, flags, fliers, apparel and other paraphernalia, that are of a political, offensive and/or discriminatory nature, containing wording, symbols or any other attributes aimed at discrimination of any kind against a country” are not allowed.