The Swiss special federal public prosecutor has opened criminal proceedings against FIFA president Gianni Infantino.

The proceedings follow an investigation by the prosecutor, Stefan Keller, into complaints regarding meetings between Infantino, Swiss attorney general Michael Lauber and the chief public prosecutor of the Upper Valais, Rinaldo Arnold.

A statement from the Swiss federal council said Keller has concluded that there are "indications of criminal conduct" in connection with those meetings.

Football's world governing body is based in Zurich and subject to Swiss law.

Lauber last week offered to resign after a court concluded he had covered up a meeting with Infantino and lied to supervisors while his office investigated corruption surrounding soccer's governing body. He officially tendered his resignation, with his last day of active duty set for 31 August.

While Lauber had acknowledged two meetings with Infantino in 2016, he had denied a third meeting reported by media to have occurred in 2017, prompting a disciplinary probe by the agency that supervises the attorney general's office.

He later said he did not recall the third meeting but that it must have occurred based on diary entries and text messages.

Both men have denied any wrongdoing but the authority overseeing Lauber's Office of the Attorney General (OAG) said that Keller had found indications of criminal conduct related to their meetings.

"This concerns abuse of public office, breach of official secrecy, assisting offenders and incitement to these acts," the AB-BA watchdog overseeing the OAG said in a statement.

The authority said Keller had now opened proceedings against both Infantino and Arnold, a regional public prosecutor who was involved in the meetings, and was seeking parliamentary approval to have Lauber's immunity from prosecution waived.

The statement concluded: "The presumption of innocence applies to attorney general Michael Lauber, FIFA president Gianni Infantino and chief public prosecutor Rinaldo Arnold."

FIFA said it acknowledged the decision of the prosecutor and that it and Infantino "remain at the disposal of the Swiss authorities and will, as we have always done, co-operate fully with this investigation".

Infantino added: "People remember well where FIFA was as an institution back in 2015, and how substantial judicial intervention was actually required to help restore the credibility of the organisation.

"As president of FIFA, it has been my aim from day one, and it remains my aim, to assist the authorities with investigating past wrongdoings at FIFA.

"FIFA officials have met with prosecutors in other jurisdictions across the world for exactly these purposes."

Infantino was asked about the case at last month's FIFA Council meeting, and described the formal complaints against him then as "absurd".

"To meet with the head prosecutor or attorney general of Switzerland is perfectly legitimate and it's perfectly legal," he said.

"There was a mountain of questions (after he was elected concerning the previous regime under Sepp Blatter).

"So it's legitimate to offer to contribute to the Swiss Attorney General about the clarification of these events, hoping that those who have done criminal acts and damaged FIFA will be held to account for that."

Arnold said: "I take note of the fact that a lawsuit has been opened. This is actually a logical step to clarify the facts. It should be mentioned that a case against me was closed last spring last year." 

Infantino was elected in 2016 to replace the disgraced Blatter, who also become the subject of criminal proceedings in 2015.

Blatter, suspected of criminal mismanagement, was banned by FIFA's own ethics committee although the investigations against him are still ongoing and he has not been charged. He denies wrongdoing.

On being elected, Infantino promised to clean up FIFA and to put the focus back on football.

FIFA was embroiled in the worst corruption scandal in its history in 2015 which led to several officials being indicted in the United States on corruption-related charges.