The Federal Bureau of Investigation is now looking into Blatter's role in tens of millions of dollars of bribes given to football officials, according to US media.
Interpol meanwhile put six other suspects, including two former FIFA executive members, on its most wanted list.
Critics of the 79-year-old Swiss official rejoiced at his thunderbolt announcement on Tuesday that he would stand down as soon as an election can be held to find a successor.
His decision sparked a global race to take over as head of the world's richest and most powerful sporting federation.
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But Platini did call off a meeting of the European confederation to discuss the FIFA crisis in Berlin on Saturday because of the "uncertain and unpredictable events" surrounding the world body.
Blatter, who has ruled FIFA for 17 years, won a fifth term in an election on Friday but renewed criticism of his reign and new corruption revelations about FIFA forced him into a corner.
Blatter vowed that in his remaining months in office he would "focus on driving far-reaching, fundamental reforms that transcend our previous efforts."
US authorities have charged 14 football officials and sports company executives over more than $150 million in bribes. US Attorney General Loretta Lynch refused Wednesday to comment on reports that Blatter is also a FBI target.