FIFA President Sepp Blatter said corruption scandals that rocked the world soccer organization have brought "shame and humiliation" on the sport.

"The next few months will not be easy for FIFA. I am sure more bad news will follow but it is necessary to begin to restore trust," Blatter said, speaking publicly for the first time since U.S. and Swiss officials unveiled major corruption investigations of the organization and seven high-ranking current and former FIFA officials were arrested Wednesday.

Bern and Zurich, Switzerland
Bern and Zurich, Switzerland

Blatter, 79, who spoke at the opening of the FIFA Congress in Zurich, said, "Actions of individuals, if proven, bring shame and humiliation and demand action and change from us all. We cannot allow the reputation of football and FIFA to be dragged through the mud any longer. It has to stop here and now."

"I know many people hold me ultimately responsible for the actions and reputation for the global football community," Blatter said, adding, "I cannot monitor everyone all of the time. If people want to do wrong, they will also try to hide it.

"But it must fall to me to be responsible for the reputation and well-being of our organization and to find a way forward to fix things," he said.

Calls for resignation

Meanwhile, two major European football associations called on Blatter to resign, ahead of presidential elections planned for Friday.

FILE - UEFA President Michel Platini, shown in May
UEFA President Michel Platini addresses a news conference after a UEFA meeting in Zurich, Switzerland, May 28, 2015.

The president of the Union of European Football Associations (UEFA), French football legend Michel Platini, spoke openly about the FIFA scandal and took issue with Blatter's refusal to resign.

"We went to his office and I renewed my advice to him to go and that he should resign," Platini said. "That he should realize the moment was not a good one and to have the courage, honesty and grandeur to realize that it wasn't good.”

According to Platini, Blatter refused, arguing that it was too late, since the electing congress was about to start.

The German Football Association (DFB) has also demanded Blatter's resignation, citing the credibility issue with him.

“It is time for a change, definitely, and that it is not a question of whether Blatter is guilty or not guilty,” DFB president Wolfgang Niersbach said. “It is time for change because we need FIFA as an institution with credibility and that is difficult, maybe impossible without a change at the top,” he added.

Blatter rejected their demands.

Sponsors' reactions

Also, sponsors are calling for football's governing body FIFA to make changes while its regional federations debate the future of its often-criticized leader.

Credit card company Visa made the strongest statement after the U.S. Justice Department unveiled an indictment Wednesday charging 14 people with offenses that include racketeering, wire fraud and money laundering.

WATCH: US Attorney General Loretta Lynch announces charges

Visa expressed "profound" disappointment and said that without reforms, the company would reassess its sponsorship of FIFA.

"As a sponsor, we expect FIFA to take swift and immediate steps to address these issues within its organization," the credit card company said in a statement. "This starts with rebuilding a culture with strong ethical practices in order to restore the reputation of the games for fans everywhere."

Coca-Cola Co. also said it has repeatedly expressed concern about the allegations and expects FIFA to thoroughly address the issues, while Adidas called on FIFA to "follow transparent compliance standards in everything they do."

The United Nations is also reviewing its partnerships with FIFA following allegations of widespread corruption, U.N. spokesman Stephane Dujarric said Thursday, a day after the scandal erupted. The U.N. and FIFA have partnerships, for example, to promote health, gender equality and for child protection.

FILE - Jordan's Prince Ali Bin Al Hussein, FIFA pr
FILE - Jordan's Prince Ali Bin Al Hussein, FIFA presidential candidate, attends the Soccerex Asian Forum on developing the business of football in Asia at the King Hussein Convention Center at the Dead Sea, Jordan, May 4, 2015.

Leadership vote

The Asian Football Confederation said Thursday that Friday's scheduled vote for FIFA's president should go ahead as planned and that it supports Blatter.

Blatter is expected to win a fifth term in Friday's election against Jordan's Prince Ali.

But The Football Federation of Australia, FFA, which has supported Blatter since he first assumed the presidency in 1998, said it would support the prince this year.

"FFA believes that profound change within FIFA is needed as soon as possible to address issues of governance and transparency," a statement said. "This belief will be reflected when Australia casts its vote in the presidential election, should it proceed on Friday in Zurich."

Human Rights Watch (HRW) said Thursday that whoever serves as FIFA's next president should take steps to ensure future World Cup host cities focus on basic human rights.

"The arrests have spotlighted FIFA's unaccountable system, but there should also be a new scrutiny of the conditions for a vast army of migrant laborers who are building massive new infrastructure to host the World Cup," said Minky Worden, HRW's director of global initiatives.

Thomas Bach, president of the International Olympic Committee, said FIFA needs to learn from the Olympic movement's experience and become more transparent if it is to regain its credibility.

In 1998, the IOC was caught in its own bribes-for-votes scandal involving the 2002 winter Olympics in Salt Lake City, Utah. That was the catalyst that led to wholesale reforms within the organization.

Bach, who spoke Thursday after Blatter addressed delegates, said, "These are sad and difficult days for FIFA. ... I am confident that following a way of transparency with  determination, you, the guardians of football, will overcome these challenges and you will make your sport shine once again."

Federal agents carry out boxes of evidence taken f
Federal agents carry out boxes of evidence taken from the headquarters of the Confederation of North, Central America and Caribbean Association Football (CONCACAF,) May 27, 2015, in Miami Beach, Fla.

US, Swiss investigations

The U.S. investigation stretches back to 1991 with allegations that include sports media executives paying or agreeing to pay $150 million in bribes in exchange for marketing rights to tournaments, as well as corruption related to the 2011 FIFA presidential election and the sponsorship of Brazil's soccer federation by a U.S. sportswear company.

Authorities in Zurich, Switzerland, arrested seven people early Wednesday, while the FBI raided the Miami offices of CONCACAF, the regional body governing North and Central America.

U.S. Attorney General Loretta Lynch called the allegations "rampant, systemic and deep-rooted" corruption that "profoundly harmed a multitude of victims."

"They did this over and over, year after year, tournament after tournament," Lynch said. "They corrupted the business of worldwide soccer to serve their interests and to enrich themselves."

Swiss authorities also unveiled a separate investigation into allegations of mismanagement and money laundering connected to the awarding of the 2018 and 2022 World Cups.

FIFA's ethics committee investigated similar allegations, and concluded in November that there were only "limited" ethics breaches and not sufficient evidence of bribery in awarding the tournaments.

FIFA said it is fully cooperating with both U.S. and Swiss authorities, and that it is in the "highest interest" of the organization that all questions are answered.

Some material for this report came from AP and Reuters.