The Houston Dynamo was caught off guard by a recent letter from FC Dallas and Toyota Stadium implementing sanctions on Dynamo support groups for future games at Toyota Stadium.

Team president Chris Canetti was surprised after seeing the letter making the rounds Tuesday night on social media; accusing Dynamo support groups of unacceptable behavior before, during and after a recent match at Dallas' stadium on May 28.

The Dynamo is standing behind its fan groups, however.

FC Dallas spokesperson Gina Miller verified the letter Tuesday night to KHOU 11 Sports Anchor Jason Bristol, adding the sanctions were "league-driven."

Major League Soccer did not respond to an email or phone call from Bristol.

Houston meets Dallas at BBVA on June 23.