NEW YORK: Sepp Blatter is the focus of an FBI corruption investigation in the United States, American media reported Tuesday, shortly after his shock resignation as president of FIFA.

An FBI spokesman said the bureau was “making no comment” beyond last week's announcement by Attorney General Loretta Lynch and FBI Director James Comey that FIFA was being investigated for corruption.

Blatter has not yet been identified publicly as a target of the investigation.

The New York Times and ABC News reported the investigation, citing unnamed law enforcement officials and sources familiar with the case, but gave no further details.

ABC News said the FBI and US prosecutors are investigating Blatter as part of the probe that led to last week's indictments.

“Now that people are going to want to save themselves, there's probably a race to see who will flip on [Blatter] first,” one source told ABC News.

Another source said: “We may not be able to collapse the whole organisation but maybe you don't need to,” referring to typical federal law enforcement tactics of getting people to provide information about their superiors.

Blatter, who has ruled football's governing body for 17 years, said he would remain in charge until a special congress can choose a new leader and vowed to pursue strong reforms in that time.

He had only just won re-election from FIFA members on Friday.

Lynch announced last week that the United States had indicted 14 FIFA executives and sports marketing executives accused in a $150 million bribery scheme.

Seven FIFA officials were arrested in a dawn swoop by Swiss police on a luxury five-star hotel in Zurich ahead of the body's executive meeting, which saw Blatter briefly re-elected.

At the time, US prosecutors said the investigation was ongoing but would not be drawn on the possible charges against other senior FIFA figures and pointedly refused to answer questions about Blatter.

Blatter took over an international federation facing financial difficulties and turned it into a money-spinning operation that, between the 2010 and 2014 World Cups, made $5.7 billion. FIFA now has a cash mountain of $1.5 billion.

But scandal has never been far from his office. There were allegations over the vote that elected him in 1998, and over the collapse of the ISL sports marketing giant in 2001.

Blatter resignation opens new FIFA race

Sepp Blatter's shock resignation opened up a new race to become president of FIFA with a mission to reform football's scandal-tainted world body.

The names of UEFA president Michel Platini, Prince Ali bin al Hussein, who challenged Blatter in a vote last Friday, and Portuguese football great Luis Figo were immediately pushed forward.

But no figure made an official declaration.

“There will be jostling for position. The election will take time,” commented one FIFA executive member in the hours after the 79-year-old Blatter gave in to pressure to stand down over a bribery scandal that hit the football body.

French football legend-turned-politician Platini is the best known of the potential runners.

The 59-year-old, three time winner of the Ballon d'Or, established his administrator credentials as organiser of the 1998 World Cup. He has headed UEFA since 2007.

Platini decided last year not to run against Blatter in the election on Friday. He did not rule out an attempt in 2019 however. But Platini's own reelection in April to a new term in charge of the wealthiest and most powerful of football's regional confederations could also hold him back from a bid for FIFA.

Platini praised the “difficult” and “brave” decision made by Blatter to stand down. But he gave no sign of his own intentions.

Jordan's Prince Ali, who was a FIFA vice president until Friday when he lost the presidential election to Blatter, made it known through a spokesman that he is “ready” for football's top job.

“As for new elections, Prince Ali is ready,” Sala Sabra, vice-president of the Jordanian football federation which the prince heads up, said.

The prince, Sabra added, was also ready “to take up the presidency immediately” if asked.

Blatter said he would remain in office until a new election is held. But the extraordinary congress is not expected until between December this year and March 2016.

In Friday's election, Blatter won 133 votes — seven short of the required majority — to Prince Ali's 73 in the first round of voting.

The prince, standing on a reform ticket, withdrew before the second round, allowing Blatter in for his short-lived fifth term.

Luis Figo welcomed Blatter's departure by saying: “Now we should, responsibly and calmly, find a consensual solution worldwide in order to start a new era of dynamism, transparency and democracy in FIFA.”

Figo was given strong backing by the Portuguese for his own candidacy, withdrawn in the week before voting to give Prince Ali a better chance.

Portuguese Football Federation president Fernando Gomes said a Figo run this time would be “an individual choice”.

Dutch Football Association chief Michael Van Praag also pulled out of the race to help Prince Ali. He told Dutch media he would test opinion at a UEFA meeting in Berlin on Saturday “and then consider my plans”.

Van Praag had said he would be a stop-gap president to carry out emergency reforms if elected last week.

Asia and Africa, strong supporters of Blatter, could also put forward candidates now that the field is open. Sheikh Ahmad Al-Fahad Al-Sabah, the Kuwaiti head of the Olympic Council of Asia, became a new member of FIFA's executive committee on Saturday. But he would probably have to choose between the OCA and FIFA.

Asian Football Confederation president Shaikh Salman bin Ebrahim al Khalifa, a Bahraini royal, is also a potential choice.

Confederation of African Football chief Issay Hayatou stood against Blatter in 2002 and then became a loyal ally. But the Cameroonian is now 68 and undergoes kidney dialysis. He has also been reprimanded in the past for accepting cash payments. He denies any wrongdoing.