Lance Armstrong has responded angrily to reports - criticised by the United States Anti-doping Agency - that his former team-mates have been handed six month suspensions in exchange for giving evidence in a doping case allegedly implicating the seven-time Tour de France champion.

Suggestions bans suspended until the end of the season have been issued to team-mates of Armstrong for giving evidence in the case have been dismissed by those allegedly involved and USADA, who last week confirmed they are to file formal doping charges against the Texan.

Armstrong repeatedly and strenuously denies any wrongdoing and described the investigation as a "vendetta".

Armstrong wrote on Twitter: "So let me get this straight...come in and tell @usantidoping exactly what they wanted to hear...

" exchange for immunity, anonymity, and the opportunity to continue to race the biggest event in cycling..

"This isn't about @usantidoping wanting to clean up cycling - rather it's just plain ol' selective prosecution that reeks of vendetta."

USADA chief executive Travis T. Tygart criticised the speculation surrounding the case and insisted nothing has been determined and that no individual cases have been addressed.

In a statement, Tygart said: "USADA's investigation into doping in the sport of cycling continues.

"No individual cases have been finalised, and any attempt to guess at whom potential witnesses might be only leads to inaccurate information being reported and subjects those named to unnecessary scrutiny, threats and intimidation.

"It is important to remember that the truth would often be suppressed without witnesses who at great cost to themselves are willing to tell the truth under oath about what they saw and experienced, and any attempt to circumvent the proper procedures in order to bully or silence people who may or may not be witnesses cannot be tolerated."

Armstrong and USADA's responses came after the story broke in Europe before the start of today's fifth stage of the Tour in Rouen.

Two of his former team-mates Christian Vande Velde and David Zabriskie ride for Garmin-Sharp, whose team boss Jonathan Vaughters, also a former team-mate of Armstrong's, gave short shrift to the claims.

Vaughters, chief executive of Slipstream Sports, the parent company of the Garmin-Sharp team, wrote on Twitter: "Regarding the Dutch media report: No 6mos (sic) suspensions have been given to any member of Slipstream Sports. Today or at any future date."

A Slipstream Sports statement added: "Media reports of suspensions are untrue.

"As we have always said, we expect that anyone in our organisation who is contacted by any anti-doping or government authority will be open and honest with that authority, but, at this moment, we - our organisation, our riders and our staff - are focused on the Tour de France."

George Hincapie is riding in a record 17th consecutive Tour, having been a team-mate of Armstrong in each of his seven triumphs, and is seeking to help BMC Racing team-mate Cadel Evans successfully defend the yellow jersey.

BMC Racing team president Jim Ochowicz said: "We've not received any notification from any authority about this issue at all."

Hincapie added: "I'm just disappointed with this thing being brought up once again.

"BMC's got nothing to do with this. Cadel's focus is to try to win the Tour and I'm here to help him do that.

"I'll continue to do that and try not to let anything get in my mind besides that."

Asked whether he has spoken to Armstrong recently, Hincapie added: "I haven't in a while. I feel bad that he's going through all this. Lance has done so many things for the sport."

Levi Leipheimer (Omega Pharma-QuickStep) and Chris Horner (RadioShack-Nissan-Trek) are also former team-mates of Armstrong and are currently riding in the Tour.

Johan Bruyneel, directeur sportif of the RadioShack-Nissan-Trek team and a former manager of Armstrong's teams, chose to miss the Tour due to the ongoing case and also denies any wrongdoing.

Hincapie, Leipheimer, Vande Velde and Zabriskie last month each opted not to be considered for the United States Olympic team, sparking rumour and speculation over their decisions.

Responding to the reports, a spokesperson for the International Cycling Union told Press Association Sport: "UCI has requested that USADA provide information on what has been reported in the media.

"So far UCI has received no answer from USADA on the matter.

"At this stage it's just hearsay and we are unable to comment further."

Armstrong, 40, has always strenuously denied all allegations of doping and reacted angrily when the USADA initiated legal proceedings over "allegations of anti-doping rule violations" during his time with the United States Postal Service (USPS) cycling team. He said the agency were dredging up discredited accusations.

Armstrong survived testicular cancer early in his career and went on to win seven consecutive Tour titles from 1999 to 2005 while competing for USPS and Discovery Channel.

He retired in 2005, but returned in 2009, riding for Astana and RadioShack before retiring for a second time in February 2011, taking up triathlon earlier this year.