The decision by the FIFA executive committee to publish ethics investigator Michael Garcia's report, with witnesses' names taken out, is aimed at lifting the cloud of suspicion that has dogged the 2018 and 2022 tournaments in Russia and Qatar and the December 2010 vote that sent the World Cup to those countries for the first time.
Blatter said only if major new evidence of bidding irregularity comes to light could those votes be reconsidered.
"There is no reason to say that our decisions were wrong. So we will go on sticking to our decisions," Blatter said, speaking through a translator. "There must be huge upheaval, new elements must come to the fore, in order to change this."
The 78-year-old Blatter, who is seeking a fifth term as president, said the decisions by the FIFA executive committee will allow the governing body to move on from four years of controversy.
"We have been in a crisis," Blatter said. "The crisis has stopped because we again have the unity in our government."
All 25 voting members of the executive committee, including three of them placed under investigation by Garcia before he suddenly resigned in protest this week, agreed that the findings of the American lawyer's two-year probe into the 2018 and 2022 voting should be published, Blatter said.
That will happen after the investigations that Garcia initiated into those three people and two others are concluded, he added. Those probes are now in the hands of Cornel Borbely, Garcia's former deputy now promoted in his place.
"There comes a situation where there must be shown unity and there must be shown a determination to end a situation which has created a lot of problems," Blatter said.
The turnaround — FIFA had previously insisted that the 430-page investigation must remain confidential — follows Garcia's resignation this week and parting accusations that FIFA leadership is weak and that the organization cannot be reformed. That increased pressure on FIFA to publish his findings.
"The pressure to do so was very, very strong," executive committee member Theo Zwanziger said. "There were quite a few voices against the publication of the report but there was a very long discussion.
"The fallout from not publishing is worse than transparency," Zwanziger added. "It's a good day for FIFA."
Blatter noted, however, that Garcia's work can only be published after FIFA's strict secrecy rules have been satisfied and the investigations against the five people have been closed.
They include three current FIFA executive committee members — FIFA vice-president Angel Maria Villar of Spain, Michel D'Hooghe of Belgium and Worawi Makudi of Thailand. There are also cases against Franz Beckenbauer, the Germany great and former FIFA executive committee member, and former Chile football leader Harold Mayne-Nicholls, who led FIFA's inspection team that evaluated the nine World Cup candidates in 2010.
If any of those five individuals are found guilty of wrongdoing they can appeal to the Court of Arbitration of Sport, potentially further delaying the publication of the full investigation.
"Let us hope that the report can now be published as quickly as possible. The credibility of FIFA depends on it," said UEFA President Michel Platini, a FIFA vice-president and member of the executive committee.
Domenico Scala, who heads a FIFA audit panel and recommended to the FIFA executives that they should agree to publish Garcia's findings in "an appropriate way" with some redactions, said he could not predict when the report will finally see the light of day.
"I hope fast," Scala said. "Frankly speaking, I don't know."
Until now, the only indication of what might be in Garcia's report has come from a 42-page summary prepared by FIFA ethics judge Joachim Eckert. Garcia, however, complained that Eckert's summary misrepresented his findings. He appealed to FIFA and then resigned on Wednesday after his appeal was rejected.
Blatter, sounding combative, again indicated that he will stand for re-election next year and brushed aside suggestions that his leadership is weak.
"It is not my duty to evaluate myself. If you claim that I am a weak leader, then kindly ask the members of the executive committee," Blatter said. "This about weak leadership, let's leave that aside. I am what I am."
Dealing with the Garcia report overshadowed other important decisions from the meeting. Notably, the executive committee said it wants an independent body to be created to ensure that Qatar tackles widely documented labour abuses. Hundreds of migrant workers have died, many apparently from cardiac arrest, in the huge construction drive to ready the Gulf nation for 2022.
"Regarding Qatar and the question of human rights ... FIFA is putting pressure on," Zwanziger said.
In other decisions, FIFA:
—Chose June 14, 2018, for the opening game of the 2018 World Cup in Russia, with the final on July 15.
—Boosted prize money for the Women's World Cup by 50 per cent from $10 million to $15 million for the 2015 edition, with $2 million for the winning team.
—Opened the possibility for international referees to continue beyond the age of 45 if they pass annual fitness tests.
AP Sports Writer Rob Harris in London and Ciaran Fahey in Berlin contributed to this report.