FIFA responded after Swiss daily Blick reported comments made by Blatter late Thursday at an event to thank construction workers at FIFA's new museum in Zurich.
Blatter said that he technically did not resign on June 2 but had pledged to leave at a special election congress, which is still being organized.
"I have not resigned, but I put back my mandate at the disposition of the next extraordinary congress," the outgoing FIFA leader said in Blick's report.
In his speech on June 2, Blatter did not use the word "resign" and also pledged he would not be a candidate at the next election, which is expected to be held between December and March.
"We can confirm the quotes in Blick are accurate," FIFA said in a statement. "However, they are fully in line with the speech of the President on June 2."
Blatter has a tendency to play with words, leaving FIFA to clarify his meaning.
Previously, Blatter has spoken of a "mistake" in the awarding of the 2022 World Cup before it was later explained that he meant the error lay in choosing to play in the summer heat in Qatar. The tournament is now scheduled for November-December 2022.
Doubts about Blatter's promise to leave office were also fueled by Swiss public relations executive Klaus Stoehlker, who served as a campaign adviser ahead of Blatter's recent re-election win.
"The president is fully prepared to step down but only if there is a competitor who is able to take over the job," Stoehlker told the AP on June 15, comparing Blatter to an ancient Swiss warrior. "The Swiss warrior takes decisions, and perhaps when the war is changing, he makes a new decision."
Blatter has not fully explained why he announced he would leave office just four days after winning re-election to a fifth term amid a crisis provoked by American and Swiss federal investigations of corruption linked to FIFA.
American law enforcement officials have confirmed that Blatter is a target of their investigation into widespread bribery and racketeering linked to broadcast rights and hosting votes for international tournaments.
Four football and marketing officials have already made guilty pleas and 14 more were named in an indictment published on May 27.
Seven of the indicted men were arrested on corruption charges in early morning raids on FIFA's favourite luxury hotel in Zurich and have since been detained awaiting extradition to the United States.
On Friday, one of the seven was denied release on bail by Switzerland's Federal Criminal Court.
The Swiss court said "there was a risk that the appellant would abscond if released."
The court did not identify the man, though noted that his "advanced age and poor state of health" were not accepted as grounds for release.
The detainees include two 83-year-old men: former FIFA vice-president Eugenio Figueredo of Uruguay and Jose Maria Marin of Brazil, who headed the 2014 World Cup organizing committee.
American authorities must file formal extradition requests by July 3 to the Swiss federal justice ministry.