PORTLAND, Ore. — Major League Soccer’s new policy that bans political displays at matches is stirring controversy in the Pacific Northwest, where supporters’ culture is often intertwined with politics and social issues.

The Seattle Sounders and the Portland Timbers have banned signs and flags with the “Iron Front” symbol, which they say has become appropriated by some in the loosely structured antifa movement, at times in the context of violence.

The symbol of three arrows pointing downward and to the left dates to an anti-Nazi paramilitary organization formed in Germany in the 1930s. Supporters’ groups maintain the symbol represents opposition to fascism and persecution — a human rights issue, not a political stance.

“With the recent rise in targeted attacks against so many groups — LBTGQ+, immigrants, women, religious groups, and more — and the presence of fascists in our stadiums, this symbol represents our firm stance of combating hatred in soccer, our communities, and our world,” the board of directors for Portland’s 107 Independent Supporters Trust said in a statement. The group represents fans of both the Timbers and the National Women’s Soccer League’s Portland Thorns.

The league’s new fan code of conduct, implemented this season, prohibits “using (including on any sign or other visible representation) political, threatening, abusive, insulting, offensive language and/or gestures, which includes racist, homophobic, xenophobic, sexist or otherwise inappropriate language or behavior.”

MLS president and deputy commissioner Mark Abbott said the league worked with all its teams to devise the policy.

“I think it was the belief of the league and the clubs that fans are at our games to enjoy the game and that there is a place for third-party political organizations or groups to express their views, but that place isn’t within our stadiums,” Abbott said.

MLS is the only professional league among the top five in the United States with a code of conduct that expressly bans political signage. Policies for the NFL, NHL, NBA and MLB mostly deal with fan conduct, like abusive behavior or language, and intoxication. The NBA prohibits “obscene or indecent messages” on signs.

MLS is also the only league to specifically target racist, homophobic, xenophobic and sexist language or behavior, which was lauded by supporters’ groups.

But some questioned the inclusion of political displays as too vague.

“We, as an organization, feel strongly on ensuring that displays of human rights are not mistaken for political statements. Political engagement is sometimes necessary in securing human rights for all, but that does not make the message of human rights inherently political,” the Independent Supporters Council of North America said in a statement following the release of the policy.

Earlier this season, a fan waving a Trump 2020 flag was removed from Providence Park.

Sounders supporters took issue when the Iron Front symbol was included with mentions of far-right groups Patriot Prayer and the Proud Boys in a letter from team management that explained the ban.

But the link to antifa has spurred some to take action. Last weekend a dozen activists confronted fans taking part in the traditional March to the Match. The group also tried to get into a pregame party at a nearby bar but was turned away by bouncers.

There was one scuffle but no arrests were made.

The incident came on the same weekend as the mass shootings in El Paso, Texas, and Dayton, Ohio. In Philadelphia, Union captain Alejandro Bedoya rushed to the sideline after a goal and shouted into an on-field microphone: “Hey Congress, do something now! End gun violence! Let’s go!”

While Bedoya’s statement was clearly political, MLS did not take any disciplinary action. Bedoya was voted the league’s Player of the Week even though he was not included on the ballot.

Anne M. Peterson is an Associated Press writer.