Is Sepp Blatter set to take a U-turn, stand again for FIFA president elections?

Sepp Blatter could still perform a U-turn on his promise to stand down as FIFA president, a former adviser said on Monday, while FIFA did not directly deny the possibility.

Klaus Stoehlker, who advised Blatter during the recent election campaign, told Sky News that Blatter could remain head of world soccer's governing body if a "convincing candidate" to replace him did not emerge.

FIFA said in a statement that Stoehlker, who was in a meeting when contacted by Reuters and unable to comment, was no longer working with Blatter.

"Klaus Stoehlker's mandate from the FIFA President ended on 31 May 2015. The FIFA President would like to point to his remarks from 2 June," it said, referring to Blatter's announcement that he would call a new election in which he would not be a candidate.

English Football Association chairman Greg Dyke does not think Blatter will have a change of heart.

"I think it (a U-turn) is extremely unlikely. I think it would be very controversial," Dyke told Reuters

"There would be a rebellion amongst a lot of people (if he did)."

However, Blatter has changed his mind in the past. In 2011, he said his fourth mandate would be his last but he stood again this year.

Blatter was re-elected for a fifth term as FIFA president on May 29 when his opponent Prince Ali Bin Al Hussein withdrew after Blatter had won the first round of voting by 133 to 73.

Four days later, as corruption allegations continued to batter FIFA, Blatter said he would stand down and call a new election, due to be held between December and February.

The FBI is investigating bribery and corruption at FIFA, including scrutiny of how soccer's governing body awarded World Cup hosting rights to Russia and Qatar.

US Assistant Attorney General Leslie Caldwell noted on Monday that the investigation into FIFA is not shouldered solely by the United States and is instead shared by international law enforcement partners.

The US Justice Department "has worked closely with the lead FIFA prosecutors to obtain evidence from numerous countries across the globe," Caldwell said at the Association of Certified Fraud Examiners conference in Baltimore.

"Far from acting as the world's corruption police, the United States is part of a formidable and growing coalition of international enforcement partners who together combat corruption around the world." The confusion surrounding FIFA's leadership took a new twist on Sunday when the Schweiz am Sonntag newspaper reported that Blatter, 79, may seek to stay on as president.

The report said Blatter had received messages of support from African and Asian football associations, who voted for him at the election and want him to reconsider his decision.

Blatter was honoured by the support and had not ruled out remaining in office, the newspaper said, citing an anonymous source close to him.

Africa's soccer confederation (CAF) said on Monday that it had not heard of any of its members asking Blatter to stay on.

"At CAF level we are not aware of any African countries who have written to ask Blatter to stay on," Kalusha Bwalya, a CAF executive committee member and president of the Football Association of Zambia, told Reuters.

"We feel it is better to get on with our own work in the meantime and see what everyone has to say in the next months. Everybody is waiting for clarity."

"At the moment there are a lot of rumours floating about and everyone is rushing to turn the smallest piece of information into a story."

UEFA insiders told Reuters that European soccer's governing body was left perplexed by the reports that Blatter would stand again and that the plot would be too outrageous even for a Hollywood script.

Officially, European soccer's governing body did not want to comment but the German football association (DFB) called on Blatter, who is staying on until the election, to leave quickly.

"We only know the media reports which strengthen our clear position," spokesman Ralf Koettker told reporters. "Blatter's announced resignation must be formally completed as soon as possible."

Germany coach Joachim Loew said: "As far as I can speak as a coach, FIFA must have a new structure and there has to be a certain new start because all of this has damaged football, and that was dangerous. I think resigning from a resignation should normally not happen."

However, Domenico Scala, the official overseeing the process of choosing a new president, said on Sunday that Blatter's departure was an "indispensable" part of planned reforms to soccer's governing body.