Besseberg, who led the IBU for 25 years, had been accused by the International Federation's independent External Review Commission (ERC) of favouring and protecting Russian interests, "particularly in the anti-doping context" after he was bribed by biathlon leaders in the country.

Other allegations included that member federations at the 2016 IBU Congress had been bribed to vote in favour of the 2021 World Championships being held in Tyumen in Russia.

Økokrim, Norway's national authority for investigation and prosecution of economic and environmental crime, had been investigating the case for five years.

They announced today that the alleged crimes were committed during the period 2009 to 2018, the year that Besseberg and IBU secretary general Nicole Resch resigned following the opening of the criminal investigation.

In the indictment, the 77-year-old Besseberg is accused of having received several expensive watches.

He also allegedly used prostitutes paid for by others, as well as accepted free hunting trips abroad.

Russian biathlon officials will have been among those who helped fund the gifts, according to Økokrim.

Besseberg is also accused of having used a BMW X5 for several years, while the leasing costs were allegedly paid by marketing agency Infront.

"Økokrim believes there is evidence that the defendant has received bribes continuously over a 10-year period," prosecutor and first state attorney Marianne Djupesland said. 

"The seriousness is emphasised by the breach of trust this entails in light of his office as President of the IBU."

The investigation has required interviewing a large number of people in and obtaining information from a number of countries and has been part of a joint investigation with Austria under the auspices of Eurojust, an agency of the European Union dealing with judicial co-operation in criminal matters, Økokrim said.

Authorities in Canada, the Czech Republic and Liechtenstein also helped in the investigation.

The maximum penalty for gross corruption is imprisonment for up to 10 years.

Besseberg has denied the allegations and never accepted a bribe or sought to influence the IBU's anti-doping work to the benefit of anyone, a statement from his lawyer Christian B. Hjort claimed.

"He does not want to comment on the various charges in detail, but will explain himself to the court when the case comes up there," Hjort said.

"But it should be noted that a number of the allegations that have been made against him in the past, especially the fact that he was accused of influencing anti-doping efforts in favour of the Russians and accepting large sums of cash, are not included in the indictment. 

"He is happy about that, because he believes that he has taken a hard line in his anti-doping efforts, whether the athletes have come from the east or the west. 

"He believes this may also be the origin of some of the allegations against him: that he has become unpopular in some camps."

The head of Økokrim, Pål K. Lønseth, warned that the case suggested there was widescale corruption in international sport.

"International top-level sports generate large revenues and handle large assets, while at the same time many sports associations display a low level of maturity with respect to prevention of corruption," he said.

"In context, this represents a clear risk of corruption which there is every reason to be worried about. 

"I hope international top-level sports will strengthen their anti-corruption work so that sports organisations can maintain their credibility."

The IBU welcomed the development concerning Besseberg.

"The IBU and the BIU have worked closely with the Økokrim on this complex and long running case and will continue to offer their full and unconditional support in reaching a resolution," they said in a statement.