Former Fifa executives took bribes in return for voting for Russia and Qatar to host the World Cup, according to US prosecutors.
In what could be a highly significant twist in the FBI's long-running investigation into allegations of football corruption, a new indictment was revealed in the US District Court on Monday.
The documents claim several former Fifa executive committee members "were offered or received bribes in connection with their votes".
The Department of Justice makes allegations against Nicolas Leoz, the former president of South American governing body Conmebol, and ex-Brazil federation supremo Ricardo Teixeira.
Both are accused of taking money "in exchange for their votes in favour of Qatar to host the 2022 World Cup". Qatar denies the allegations.
Disgraced former Fifa vice-president Jack Warner of Trinidad and Tobago was also allegedly paid £4m through a host of offshore shell companies to back Russia's 2018 bid.
Russia beat England to win the right to host the most recent World Cup in 2018. Warner was president of the North and Central American and Caribbean confederation Concacaf.
Another former Fifa ExCo member - Guatemala football chief Rafael Salguero - was allegedly promised a bribe to vote for Russia.
Leoz died last year under house arrest in his native Paraguay, having fought extradition to the US. Teixeira has been banned from the game for life by Fifa for taking bribes for marketing and media rights for football competitions between 2006 and 2012.
Teixeira and Warner, who is also banned for life, have avoided extradition to the US. Salguero was banned last year, having admitted corruption.
Former executives at US television giant 21st Century Fox have also been charged in the indictment with making payments to South American football officials to secure broadcast rights.
"The profiteering and bribery in international soccer have been deep-seated and commonly known practices for decades," said FBI assistant director-in-charge William Sweeney.
"The FBI... are investigating the illicit handshakes and backroom deals hidden in the infrastructure of soccer events, venues and marketing contracts.
"The first public charges date back to 2015. This should illustrate to everyone still hoping to score millions corruptly, we're going to find you."
What is the background?
Almost 10 years have now passed since Fifa controversially voted for Russia and Qatar to host the sport's showpiece event.
But it was only in 2015, following a dramatic dawn raid at a Zurich hotel close to the governing body's headquarters, that the US Department of Justice announced it was investigating football and TV executives enriching themselves through the game.
The scandal sparked the worst crisis in Fifa's history, with its disgraced president Sepp Blatter eventually standing aside.
A total of 42 people have been indicted, with 26 pleading guilty.
How important could this be?
With Russia staging its World Cup almost two years ago, the focus of the potential impact of these fresh allegations will be on Qatar as it enters the final phase of preparations for the event.
This is not the first time officials have been accused of corruption linked to the Gulf state's bid during the sprawling FBI probe.
In 2017 Alejandro Burzaco, a former TV executive, told a jury in New York that Leoz, Teixeira - and the now former Argentina football chief Julio Grondona - had been paid to vote for Qatar, which beat the US in the vote.
But never before have US prosecutors formally laid out in such detail how the alleged corruption was conducted.
However, the indictment does not specify who was behind the alleged bribery.
Despite years of suspicion over how they won the vote, Qatar and Russia have always denied any wrongdoing, and both were effectively cleared by Fifa's own investigation in 2017.
But Fifa may find itself under renewed pressure to reopen an inquiry into how the votes were won.
On Tuesday, Fifa said it would "continue to provide full cooperation" and is "closely following these investigations".
A statement read: "It is important to point out that Fifa has itself been accorded victim status in the US criminal proceedings and senior Fifa officials are in regular contact with the US Department of Justice.
"The Fifa ethics committee has already imposed sanctions, including life bans, on football officials mentioned in this process."
In response to the accusations, Alexei Sorokin, chief executive of Russia's 2018 World Cup, told the Interfax news agency: "This is only the opinion of lawyers. We have repeatedly said that our bid was transparent.
"At the time we answered all questions, including from the investigation branch of Fifa and from the media, we handed over all needed documents.
"We have nothing to add to this and we will not respond to attempts to cast a shadow on our bid."
Qatar's Supreme Committee for Delivery Legacy (SC) said in a statement it "strongly denies the allegation" contained within the court papers.
It added: "Despite years of false claims, evidence has never been produced to demonstrate that Qatar won the rights to host the Fifa World Cup 2022 unethically, or by means that contravened Fifa's strict bidding rules.
"The SC maintains that it strictly adhered to all rules and regulations for the 2018/2022 Fifa World Cups bidding process and any claim to the contrary is baseless and will be fiercely contested."