Paris Saint-Germain president and beIN Media chief Nasser al-Khelaifi insisted on Wednesday that "I have nothing to hide" as he faced a marathon grilling by Swiss prosecutors investigating claims of World Cup corruption.

"I asked to come to Switzerland to give my explanations. I am at the disposal of the attorney general if he wants to see me again," said the Qatari after his day-long appearance with Swiss justice officials. "I am calm and I am leaving calmly."

Khelaifi, a 43-year-old Qatari with close ties to the Gulf state's royal family, is under investigation for allegedly striking illegal media rights deals with disgraced former FIFA secretary general Jerome Valcke, who had been Sepp Blatter's right-hand man.

Khelaifi and his legal team arrived at the Swiss attorney general (OAG) headquarters in the Swiss capital Bern at about 9:30am (0730 GMT), avoiding the main entrance and two dozen reporters gathered outside.

Khelaifi and Valcke have been under investigation since March in connection with media rights for the 2026 and 2030 World Cups on allegations including corruption, bribery, criminal mismanagement and forgery of a document.

Authorities in France, Greece, Italy and Spain have cooperated with the Swiss probe, including by raiding properties.

But the OAG only went public with the case on October 12.

Khelaifi's high-profile French lawyer, Francis Szpiner, then swiftly announced that his sports tycoon client "denies any corruption" and "wanted to be heard as soon as possible" by Swiss prosecutors.

OAG spokesman Andre Marty told reporters there was "a good dozen" lawyers in the room on Wednesday, "from all parties involved", in addition to two representatives of the Swiss attorney general.

It is highly likely that FIFA lawyers were present, since the integrity of contracts signed by Valcke on behalf of world football's governing body is a central question in the case.

The beIN Media group, which is headquartered in Doha, has insisted that its World Cup rights deals were "advantageous for FIFA", rejecting any suggestion that it got favourable treatment.

The contract covers broadcasting rights for the MENA (Middle East, North Africa) region for the tournaments.

The Qatar broadcaster's offices in Paris have been raided at the request of Swiss authorities.

A raid was also carried out at a luxury Sardinian villa that, it is alleged, was put at the disposal of Valcke, who is serving a 10-year ban from all football-related activity.

The villa, set in lush grounds on the Mediterranean island and which has an estimated value of seven million euros ($8.3 million), is owned by an international real estate agency.

Valcke, a 53-year-old French national, has told the French sports newspaper L'Equipe that he "received nothing from Nasser".

An increasingly prominent figure in sports and media, Khelaifi oversaw PSG's 222 million-euro ($264 million) world record signing of Brazilian superstar Neymar in August.

PSG, who were bought by Qatar Sports Investments in 2011, are not implicated in the Swiss investigation.

The corruption accusations are the latest to rock world football which is still reeling from the events of 2015, when FIFA officials were arrested en masse at the governing body's annual conference.

They are also the latest allegations to target Qatar.

The Gulf state has found itself routinely accused of corruption since controversially winning the right to host the 2022 World Cup, charges it has always denied.