FIFA did not immediately respond to a request for comment and Blatter’s legal representative in the US declined to comment.
Switzerland's attorney general, Michael Lauber, earlier said that Swiss prosecutors could interrogate Blatter as part of an ongoing probe into FIFA, launched by the country's authorities.
Lauber confirmed that ten people have already been questioned, and refused to rule out the idea of Blatter and FIFA secretary general Jérôme Valcke being summonsed.
Senior executives of Zurich-based FIFA were charged with corruption on May 27 by prosecutors in the United States over bids for major soccer tournaments dating back 24 years and involving up to $150 million in purported bribes.
Blatter came under pressure to step down, and he announced on June 2 that he would do so.
US prosecutors have not accused Blatter of wrongdoing but his stewardship of world soccer’s governing body is under scrutiny, according to sources familiar with investigations in the United States and Switzerland.
Among those charged in the indictment are FIFA Vice President Jeffrey Webb and Jack Warner — the current and former presidents of CONCACAF, the continental confederation under FIFA, headquartered in the US.
Nicolas Leoz, former FIFA executive committee member; Eugenio Figueredo, current FIFA vice president and executive committee member; and the chief of Brazilian football, Jose Maria Marin, who oversaw last year's World Cup in Brazil, have also been charged.
