The World Anti-Doping Agency (WADA) on Thursday upped the stakes in the Tour de France's battle to save its damaged credibility by calling for a high-level summit to discuss the doping crisis.

WADA president Dick Pound admitted he was concerned by developments in the Tour this week, which have seen yellow jersey Michael Rasmussen axed from the race and long-time favorite Alexander Vinokourov fail a test for blood doping.

Now, WADA has offered to convene a high-level summit of all parties involved in cycling to have an in-depth discussion on how to deal with the problem of doping in the sport.

"Without commenting on the specifics of pending cases, WADA is deeply concerned by the multiplication of doping cases and affairs in cycling," said Pound.

"Even recent initiatives taken by cycling authorities, such as a pledge against doping and increased pressure, are obviously insufficient to deter some riders from cheating. We need to hold such a meeting urgently to see what more can be done to restore the credibility and integrity of cycling."

WADA said that an invitation to the summit will be extended to all parties involved in cycling - the UCI, organizers, professional cyclists, team members (including doctors, leaders, and other members of the entourage), and other individuals or organizations involved in the sport such as sponsors and broadcasters.

Selected members of the anti-doping community, with expertise and experience in cycling, would also be consulted.

"WADA will officially contact the parties involved in the next few days to offer to hold this summit," said WADA director general David Howman.

"Because WADA is an independent international body and has a structure which is an equal partnership between the sports movement and governments of the world, we are uniquely positioned to coordinate the fight against doping and bring together the strengths and resources of all of these partners involved.

"We are willing to further assist cycling in finding solutions to the doping issue."