A "handful" of fans belonging to the Timbers Army, the main supporters' group for the Portland Timbers in MLS, have been banned from attending games at Providence Park for three matches, multiple sources have confirmed to ESPN.

The fans were banned for waving flags that show the Iron Front symbol, which violates MLS's prohibition on political signage in its stadiums. MLS has stated that the symbol is connected to the antifa movement and thus constitutes a link to a political organization. The Timbers Army contends that the image is intended to promote inclusion, anti-fascism and anti-racism.

One source added that the fans who have been sanctioned can appeal their bans if they so choose, and that the punishments could be reduced.

The Timbers directed all requests for comment about the bans to MLS, which didn't immediately respond.

Prior to the start of the season, MLS revised its Fan Code of Conduct, which now includes a ban on political signage. While the Code of Conduct doesn't mention the Iron Front flag specifically, fans from around the league were told prior to the season that it is prohibited.

But the issue has come to a head in recent weeks. The Timbers Army, along with their Seattle Sounders counterparts -- the Emerald City Supporters and Gorilla FC, staged a silent protest for the first 33 minutes of the match between the two teams on Aug. 23. At that point in the game, the supporters from both teams began cheering and displaying flags with the Iron Front symbol.

In a statement released prior to the match, the three groups called for MLS to rescind its ban on flying the Iron Front flag, as well as remove the word "political" from its Fan Code of Conduct, calling the use of the word "inherently arbitrary."

The groups also asked MLS to work with international experts on human rights to craft language in the fan code of conduct that "reflects and supports radical inclusion and anti-discrimination."

Four days after the match, the Timbers Army said in a statement that it had been given a "general warning" by the club and the league for displaying the flag. But the Timbers Army showed the flags again during last weekend's match against Real Salt Lake, thus triggering the aforementioned sanctions.

Portland's next home match is this Saturday against Sporting Kansas City.