The FBI is "stepping up the pace" of a corruption investigation into Fifa's senior staff over the 2018 and 2022 World Cup bids, CNN reported.
Despite a Fifa report released yesterday ruling there was no corruption involved during the bidding process, FBI agents based in New York are reportedly moving ahead with their three-year-old investigation.
The FBI declined to comment on the claims, CNN added.
Lord Triesman, chair of the England 2018 World Cup bid, has criticised Fifa's "culture of secrecy" and said he is concerned that Michael Garcia's full report has not yet seen the light of day.
On the English FA's standing within Fifa, he said: "Generally speaking, I think they dislike us."
And he defended allegations that the England bid attempted to "curry favour" with disgraced former Fifa executive Jack Warner, Triesman said he was "bemused" because it was common knowledge that he and Warner "could hardly bear being in the same room as each other."
Fifa secretary-general Jerome Valcke says it is "sad" that the investigator and chairman of the organisation's ethics committee are unable to agree on the report into "such important things happening in football".
Michael Garcia earlier said Hans-Joachim Eckert's 42-page summary of his investigation contained "numerous and erroneous" inaccuracies.
FA chairman Greg Dyke says Michael Garcia's comments about his Fifa investigation "make a mockery of the whole the process."
"If the person who did the investigation says the report didn't reflect what he believed, then I'm a bit shocked by it all," he said.
"Most of the criticism is of people of who cooperated the most fully.
"If you actually cooperated, you don't get criticised, which seems very weird to me."
Football Association chairman Greg Dyke said Fifa still has questions to answer over alleged corruption in the World Cup bidding process.
Following the release of a report into Fifa's findings, Dyke told Sky Sports News: "Questions still need to be answered.
"If you read that report it says all the bids were assessed. The one that was the highest risk was Qatar and they won, and it doesn't take us any further forward on why they won."
Asked if the FA had "damaged the image of Fifa", Dyke added: "I think it's quite hard to damage the image of Fifa."
He went on to suggest that the FA - who were accused of "violating bidding rules" in the report - had been punished for "co-operating the most" with the investigation.
Britain's Fifa vice-president Jim Boyce has said Michael Garcia's investigation into alleged corruption must be published to the fullest possible extent.
“In view of the fact Michael Garcia has now stated he is not happy with the findings and is to appeal, I await with interest to see what further disclosures will be made," Boyce said.
“I have always said as much of the report as is legally possible to publish should be made public.”
Fifa must publish Michael Garcia's findings into alleged corruption in full "if it expects anyone to believe" there has not been a cover-up, Labour has said.
“Fifa has no choice but to publish Michael Garcia’s report in full, if it expects anyone to believe its claims that that there has been no cover up over allegations of corruption in the World Cup bidding process," Clive Efford, shadow minister for sport, said.
“Our FA has been accused of wrongdoing regarding its bid for the 2018 tournament in the conclusion published by the Fifa Ethics committee, but these have been attacked by Michael Garcia for being ‘incomplete and erroneous in its representations of the facts.
"The FA will only be able to defend itself if it is given full access to the report.”
Lord Triesman, the chair of the England 2018 World Cup bid, has hit out at Fifa, following the release of a report into the bidding process.
The document was highly critical of the England bid and their attempts to woo Jack Warner.
"FIFA is culturally in deep trouble. Until it resolves that it’ll continue to be a body everybody suspects of wrongdoing," Triesman said.
"FIFA has bodies which are apparently superior to any bodies which deal with law in the sense that we normally understand it.
"In those circumstances, if they don’t want something to come out, it’’ll never come out"
The Fifa investigator who probed allegations of corruption during the bidding for the 2018 and 2022 World Cups has said a report based on his findings contain "numerous and erroneous" inaccuracies.
Hans-Joachim Eckert's 42-page summary of Garcia's investigation accuses the English Football Association of breaching bidding rules but clears Qatar of any wrongdoing.
But Garcia has disputed the way his findings were represented, saying: “Today’s decision by the Chairman of the Adjudicatory Chamber contains numerous materially incomplete and erroneous representations of the facts and conclusions detailed in the Investigatory Chamber’s report.
"I intend to appeal this decision to the FIFA Appeal Committee."