Swiss prosecutors have opened criminal proceedings against Fifa president Sepp Blatter.

In a statement, the Swiss attorney general's office said that Blatter is suspected of criminal mismanagement or misappropriation, regarding a television contract signed in 2005 with Jack Warner, who was then president of the Caribbean Football Union.

The Swiss football administrator, who has headed world football's governing body since 1998, is also suspected of a "disloyal payment" to Uefa president and Fifa Executive Committee (ExCo) member Michel Platini.

The statement goes on to confirm that Swiss authorities questioned Blatter on Friday and have seized data from the president's office as part of their investigation.

Earlier on Friday, Fifa cancelled a press conference at short notice at which Blatter was due to speak for the first time since his right-hand man, secretary general Jerome Valcke, was placed on leave. Valcke was suspended from his duties following accusations regarding ticket sales at the 2014 World Cup.

Fifa have issued a statement in response, saying that they are cooperating fully with the Swiss attorney general's investigation.

"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," the statement reads. "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.