West Ham players walked off the pitch during a seven-a-side tournament in America after alleged racial abuse.
The issue happened against Dallas United in the The Soccer Tournament event on Thursday.
Dallas have withdrawn from the £1million competition following the allegation, which came towards the end of the game with Dallas leading 2-0.
Former Hammers Anton Ferdinand, Carlton Cole, Matt Jarvis, Marlon Harewood, Zavon Hines and Jimmy Walker are among those taking part in North Carolina.
It is unclear what was said – or to which player – but Ferdinand reportedly told media at the game the Hammers walked off due to racism.
A statement from TST read: “After conducting an investigation into the final moments of the match between West Ham United and Dallas United, we have concluded that Dallas United violated TST’s code of conduct.
“We have been in dialogue with leadership from both clubs and we are all aligned that the best path forward is Dallas United withdrawing from competition. All parties involved are unified in wanting to make a statement against racial insensitivity.
“We seek to run an event that is not only fiercely high stakes for all competitors, but also one in which all competitors feel safe and protected. As a result, tomorrow’s game between Dallas United and Far East United has been cancelled.”
The referee reportedly told players he did not hear what was said, before West Ham decided to walk off.
Dallas United wrote on Twitter: “In light of the shadow cast by an opposing player’s accusation during tonight’s match, the Dallas United players unanimously decided to withdraw from the remainder of the competition.
“Our coaches and staff fully support the team’s decision. We thank @TST7v7 for the opportunity to compete in the tournament.”
Wolves, Borussia Dortmund and Wrexham are among the teams taking part.