Anton Ferdinand led West Ham in walking off the pitch during a seven-a-side tournament in the US after one of their players was allegedly racially abused.
The incident occurred in their game against Dallas United in the inaugural £1m The Soccer Tournament event.
Dallas later withdrew from the tournament after organisers conducted an investigation into the allegations.
"The players made a collective decision to walk off the pitch in support of our player," said West Ham in a statement.
"As a club, everyone at West Ham United stands shoulder to shoulder in solidarity against all forms of discrimination and abuse."
Former Hammers players Carlton Cole, Marlon Harewood, Matt Jarvis and Frank Nouble were also involved in the match.
A statement from the organisers said: "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.
"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.
"All parties involved are unified in wanting to make a statement against racial insensitivity."
The game was stopped near the end of the match with Dallas leading 2-0. After a lengthy delay, West Ham players made their way off the field.
According to ESPN, the referee in charge of the match told players he did not hear what was said.
"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," a statement on the team's Twitter page read.
"Our coaches and staff fully support the team's decision. We thank TST for the opportunity to compete in the tournament."
TST is a newly created seven-a-side tournament featuring past and present players representing 32 clubs from around the world. It is taking place in North Carolina between 31 May and 4 June.
Former Premier League players Cesc Fabregas, Clint Dempsey and Landon Donovan are among those taking part, with clubs including Borussia Dortmund and Wrexham also competing.
In September 2011, former Chelsea skipper John Terry was banned for four matches and fined £220,000 by the Football Association for racially abusing then QPR defender Ferdinand.
Two months earlier, Ex-England captain Terry was cleared by Westminster Magistrates' Court of racially abusing Ferdinand.
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