Fifa has opened disciplinary proceedings against the Football Association (FA) and Scottish Football Association (SFA) for the wearing of poppies during last week's World Cup qualifier.
The English and Scottish football associations defied Fifa on Armistice Day - as players from both teams wore embroidered poppies on black armbands - after football's world governing body said the act fell under the commercial, personal, political or religious messages that it has banned.
Fifa announced that FA and SFA faced action on Thursday night with both facing the possibility of a fine, while even a World Cup points deduction is possible.
"We can confirm that disciplinary proceedings have been opened on this matter," a spokesman said.
"We cannot comment further at this stage nor speculate on any outcome or provide an estimated timeline."
Many outraged fans took to social media to express their alarm at the decision.
Some saw the high-moral stance of the move as hypocritical, in light of the scandal that rocked the organisation last year when it emerged several of its key officials were under investigation for corruption, including Sepp Blatter, who was serving as its president at the time.
The Football Association has already said it will contest any fine and believes its "legal position is right and our moral position is right".
England won the Group F match 3-0 thanks to headed goals from Daniel Sturridge, Adam Lallana and Gary Cahill.