FC Dallas has restricted the number of tickets it will give to visiting Houston Dynamo supporters' groups after incidents at a recent game between the Texas rivals.
A letter from the director of safety and security for Dallas' Toyota Stadium said only 100 tickets would be available for purchase for each of the next four games, down from 300.
The sanctions come after Dynamo fan group "El Battalion" were found to have lit two smoke bombs and one flare outside the stadium on May 28.
In addition, the Dynamo fan groups will be prohibited from bringing in "flags, banners, instruments or any other implements used to display their support of the team."
The sanctions also apply to Houston's other two recognized supporters' groups, Texian Army and Brickwall, but not to individual Dynamo fans.
FC Dallas vice president Gina Miller told the Houston Chronicle that streamers and a vulgar chant were also considered in the sanctions.
One Dynamo fan told the Chronicle that tensions with Dallas supporters escalated near the end of the game, with beer bottles being thrown. The Houston fans were then subjected to verbal abuse from their Dallas counterparts after being instructed to remain in their seats for half an hour after the game.
The Dallas Morning News reported that the decision was actually made by Major League Soccer, despite the letter being printed on FC Dallas letterhead.