Swiss prosecutors have opened a criminal investigation into Sepp Blatter, the head of the world football body Fifa.
The attorney general's office said he was being investigated "on suspicion of criminal mismanagement as well as - alternatively - on suspicion of misappropriation".
It said Mr Blatter was currently being questioned.
Earlier, Fifa cancelled a press conference at its Zurich headquarters.
The Swiss attorney general's office said the investigation surrounds a TV rights deal Mr Blatter signed with former Caribbean football chief Jack Warner in 2005.
Mr Blatter is also suspected of "a disloyal payment" in 2011 to UEFA president Michel Platini, the statement said.
Fifa said it was co-operating with the Swiss attorney general and had complied with its requests for information.
"We will continue this level of co-operation throughout the investigation," it said.