French magistrates have filed new, tougher corruption charges against former IAAF president Lamine Diack in connection with cover-ups of Russian doping.

Diack had previously been accused of "passive corruption," on suspicion he took around 1 million euros ($1.1 million) to cover up positive drug tests by Russian athletes.

An official with the Paris financial prosecutor's office said Tuesday that Diack is now accused of "active corruption," which generally involves offering money or other promises in exchange for violating a rule.

The official told The Associated Press the new preliminary charges center on suspicions that Diack bribed Gabriel Dolle, the IAAF's former anti-doping chief who also under investigation, to delay reporting of violations by Russian athletes.

The official was not authorized to be publicly named speaking about an ongoing investigation.

The preliminary charges allow magistrates more time to investigate before deciding whether to file formal charges and whether to send a case to trial. Diack, an 82-year-old former long jumper, is free on bail pending further investigation but barred from leaving France.

The latest charges are part of a multi-pronged investigation into suspected wrongdoing at the International Association of Athletics Federations that has expanded rapidly in recent months.

Russia's track and field federation was suspended by the IAAF after a World Anti-Doping Agency independent commission found evidence of systemic doping and cover-ups.

Diack's son, Papa Massata Diack, a former IAAF marketing consultant also targeted by the French corruption probe, told the BBC that his father is in "good spirits" despite the investigation.

"Suddenly they are just going to destroy all he's built over the last 16 years and all the 39 years he's spent in the IAAF, so I find it very sad and I could not recognize certain acts or certain declarations made by certain people," he was quoted as saying from Senegal.

Papa Diack also said he "totally rejects" accusations he himself had any role in blackmailing athletes or seeking money from Qatar ahead of its unsuccessful bid to host the 2017 world championships. French prosecutors suspect Papa Diack of playing an active role in an alleged "system of corruption" that sought to blackmail athletes, with demands of money to hush-up suspected doping.

A report in Le Monde on Monday alleged that another senior IAAF official, Nick Davies, tried to delay public identification of alleged Russian drug cheats ahead of the 2013 world championships in Moscow.

The French newspaper said it had a copy of an email sent by Davies to Papa Diack asking what "Russian 'skeleton' we have still in the cupboard regarding doping."

Davies, formerly director of communications at IAAF and now deputy general secretary and close associate of IAAF President Sebastian Coe, strongly denied any wrongdoing.

In a statement, Davies said the email "was brain storming around media handling strategies to deal with the serious challenges we were facing around the image of the event."

"No plan was implemented following that email and there is no possibility any media strategy could ever interfere with the conduct of the anti-doping process," he said.

Le Monde also reported last Friday that Lamine Diack asked Russia for more 1.5 million euros ($1.6 million) in 2011 to fund the political opposition in his native Senegal ahead of presidential elections. The request came at a time when the IAAF was dealing with a slew of suspected Russian doping cases.

In Senegal, President Macky Sall's Alliance for the Republic party denied it had received funding from Diack for his 2012 campaign.