ZURICH -- FIFA President Sepp Blatter has been interrogated by Swiss federal police over alleged financial corruption.

Switzerland's attorney general's office says it opened criminal proceedings against Blatter for possible criminal mismanagement and misappropriation of FIFA money.

The Swiss federal office says Blatter was interrogated after chairing a meeting of FIFA's executive committee on Friday.

FIFA vice president Michel Platini was questioned as a witness over a "disloyal payment" of 2 million Swiss francs he received from Blatter in February 2011, Swiss authorities say.

"On the one hand, the OAG suspects that on 12 September 2005 Mr. Joseph Blatter has signed a contract with the Caribbean Football Union (with Jack Warner as the President at this time); this contract was unfavorable for FIFA," the Swiss Attorney General's office said in a statement Friday. "On the other hand, there is a suspicion that, in the implementation of this agreement, Joseph Blatter also violated his fiduciary duties and acted against the interest of FIFA and/or FIFA Marketing & TV AG."

Blatter's office and FIFA headquarters were searched on Friday and data was seized, the Swiss OAG said.

FIFA issued this statement Friday:

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"Since 27 May 2015, FIFA has been cooperating with the Office of the Swiss Attorney General (OAG) and has complied with all requests for documents, data and other information. We will continue this level of cooperation throughout the investigation. Today, at the Home of FIFA, representatives from the Office of the Swiss Attorney General conducted interviews and gathered documents pursuant to its investigation. FIFA facilitated these interviews as part of our ongoing cooperation. We will have no further comment on the matter as it is an active investigation."

Earlier Friday, FIFA canceled a news conference scheduled with President Sepp Blatter without explanation, fueling the sense of turmoil surrounding football's embattled governing body.

Blatter was scheduled to meet international media at FIFA headquarters after a two-day session chairing the executive committee.

The news conference was originally scheduled to start at 2 p.m. local time but was first pushed back by one hour before FIFA announced it was canceled all together.

He had been likely to face questions about American and Swiss investigations of corruption in FIFA and a decision to suspend his secretary general, Jerome Valcke, last week.

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Before news of the criminal case against Blatter surfaced Friday, FIFA announced the 2022 World Cup in Qatar will be played over 28 days, starting on Monday, Nov. 21, and ending on Sunday, Dec. 18, Qatar's national holiday.

FIFA had decided in March to switch the 2022 tournament from June-July to avoid Qatar's summer heat. A 28-day World Cup is four fewer than usual and is designed to cause less disruption to clubs and leagues which must shut down for several peak midseason weeks.

Sepp Blatter timeline

1936 -- Born in Visp, Switzerland.

1948-1971 -- Player in Swiss amateur league.

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1956 -- Becomes member of Swiss Association of Sportswriters.

1959-1964 -- Public relations official for tourism in the canton of Valais.

1964-1966 -- Secretary general, Swiss Ice Hockey Federation.

1968-1975 -- Director at watch company Longines S.A.

1975-1981 -- FIFA technical director.

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1981-1998 -- FIFA general secretary.

1998 -- Elected FIFA president.

2002 -- Blatter accused of financial mismanagement by FIFA executive committee members. Criminal complaint filed against Blatter with Swiss prosecutors comes to nothing after Blatter is re-elected by beating Issa Hayatou of Cameroon in a vote.

2007 -- Re-elected unopposed.

2011 -- Re-elected unopposed after challenger Mohamed bin Hammam, a former ally, withdrew before being suspended by FIFA over bribery allegations.

May 29, 2015 -- Re-elected for fifth term by beating Prince Ali bin al-Hussein after reneging on pledge not to stand again.

June 2 -- Announces resignation plans as pressure mounts over escalating criminal investigations.

July 20 -- Exit date set for Feb. 26 when the presidential election is due to be held.

July 24 -- Uses in-house FIFA magazine to say the governing body will support U.S. and Swiss investigations "no matter how close to home those investigations get."

July 25 -- Interrogated by Swiss federal police over alleged criminal use of FIFA money as office is searched and data is seized.