England walked off the pitch during a match at the Under-15 World Cup after an allegation of racism by a Republic of Ireland player, which resulted in the game being abandoned.
Following an altercation between players from both sides, shortly before the end of the match in Azerbaijan on Monday, an England player approached his bench and made a complaint to coaching staff.
Match footage then showed England staff members relaying the complaint to the referee, alleging a racist slur had been said, and calling their players off.
Republic of Ireland were leading 4-1 at the time of the incident.
World governing body Fifa told BBC Sport it is investigating and gathering reports.
"Fifa is aware of an incident at the U-15 World Cup and Festival match between England and the Republic of Ireland," a spokesperson said.
"The match was abandoned by the referee following England's refusal to continue.
"The official reports are being gathered, and the matter will be referred to the independent disciplinary committee, who will decide in due course."
The Football Association and the Football Association of Ireland have been contacted for comment.
The alleged incident happened in the final minute of the Group C match in Baku.
Immediately following the allegation, England head coach Matt Thorpe was seen on the match coverage on DAZN asking for the referee to come over, before calling his players off the pitch.
After an initial report from Thorpe, the referee told England's coaching staff, "I cannot hear".
One of Thorpe's assistant coaches can then be heard telling the referee "we are reporting racism", before adding "we do not want to play".
When another official came over, talking about what would happen after the match, the assistant told him: "No, our players do not want to play".
He was later heard saying that a player was "upset".
Heated words were then exchanged between each set of coaching staff, with both saying they were trying to protect their players.
This is the first time the U15 World Cup and Festival has been played, and involves 189 countries and territories.
Matches are played in an eight-a-side format, on smaller pitches, with 20-minute halves.
England are scheduled to play their next match against Zimbabwe at 20:45 local time (16:45 GMT) on Monday, with Republic of Ireland facing Cambodia at the same time.