FIFA President Sepp Blatter hit out at unnamed lawmakers for wanting boycotts of the 2018 World Cup in Russia and the 2022 event in Qatar.
"Football should be united, sport should be united when it comes to boycotts," Blatter said at the UEFA congress on Tuesday. "Boycotts have never had any results."
Ukraine President Petro Proshenko last week urged allies to boycott football's marquee event in Russia, and other politicians have also questioned the Qatar event amid allegations of corruption and poor labor conditions.
Blatter was stung when he last faced UEFA at a pre-World Cup meeting in June in Sao Paulo, but this time he was greeted with a respectful applause by delegates from the 54 member states.
Blatter didn't spend a single word on the FIFA presidential election in May, when he stands for re-election for a fifth term.
Blatter turned down UEFA's invitation to make a campaign speech alongside his rivals, which include FIFA vice president Prince Ali bin al-Hussein of Jordan, Portugal great Luis Figo, and Dutch football federation president Michael van Praag.
The trio was scheduled to present their plans for FIFA's future later Tuesday.
Blatter praised IOC President Thomas Bach and the president of the German football federation, Wolfgang Niersbach, for voicing their outspoken rejection of any calls for World Cup boycotts.
"The autonomy of sports must be guaranteed," said Blatter, adding that football should not look away from political tensions but should try to help finding a solution. "We should do something for peace. Maybe we can help at least certain conflict situations."
Blatter called football "a symbol of unity."
"It has conquered the world and it's a treasure of diversity," he said. "Football not only brings positive emotions, but also the strength to help solving conflicts and building bridges between east and west."
Blatter also called for further action against the "evils of football," like doping and match-fixing.
"We have the will to fight against it," he said, urging UEFA to take a leading role in the process.