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The 78-year-old Swiss had pledged before his re-election in 2011 that his current term would be his last. But buoyed by a successful World Cup in Brazil and UEFA President Michel Platini opting not to stand in next year's election, Blatter believes he has the backing to win again.
"I will make an official declaration definitely in September now when we have the executive committee," Blatter said in a pre-recorded interview shown Monday at the SoccerEx conference. "I will inform the executive committee. It's a question of respect also to say then to the football family, 'Yes I will be ready. I will be a candidate.'"
Blatter, who was re-elected unopposed in 2011, had previously stopped short of confirming his candidacy for the May election. Despite ongoing corruption scandals engulfing FIFA and opposition within UEFA, Blatter appears to have retained the support of most national federations.
"A mission is never finished - and my mission is not finished," Blatter said. "I got (from) the last congress in Sao Paulo not only the impression but the support of the majority, a huge majority of national associations asking 'Please go on, be our president also in future.'"