World Cup sponsor VISA has threatened to end its partnership with FIFA over the latest crisis to engulf the world governing body.
VISA said its "disappointment and concern" was profound and called for "swift and immediate" action in the wake of a wave of arrests of football officials - including two FIFA vice-presidents - in Zurich on Wednesday on bribery, fraud and money-laundering charges following an FBI investigation.
A host of fellow sponsors have issued statements after a dramatic day in both Switzerland and the United States on Wednesday, but VISA's was the most strongly-worded of the lot.
A statement from VISA said: "Our disappointment and concern with FIFA in light of (Wednesday's) developments is profound.
"As a sponsor, we expect FIFA to take swift and immediate steps to address these issues within its organisation. This starts with rebuilding a culture with strong ethical practices in order to restore the reputation of the games for fans everywhere.
"VISA became a sponsor of FIFA because the World Cup is one of the few truly global sporting events with the power to unite people from around the world through a common love of football.
"Our sponsorship has always focused on supporting the teams, enabling a great fan experience, and inspiring communities to come together and celebrate the spirit of competition and personal achievement - and it is important that FIFA makes changes now, so that the focus remain on these going forward. Should FIFA fail to do so, we have informed them that we will reassess our sponsorship."
South Korean car manufacturer Hyundai, a top-tier World Cup sponsor, said it was "extremely concerned" by the allegations.
"As a company that places the highest priority on ethical standards and transparency, Hyundai Motor is extremely concerned about the legal proceedings being taken against certain FIFA executives and will continue to monitor the situation closely," it said in a statement.
A spokesman for McDonald's, a second-tier sponsor, said: "McDonald's takes matters of ethics and corruption very seriously and the news from the US Department of Justice is extremely concerning. We are in contact with FIFA on this matter. We will continue to monitor the situation very closely."