Seven Russian athletes have been provisionally suspended for doping offences, the International Association of Athletics Federations has announced.
Five of the seven - Yelena Soboleva, Tatyana Tomashova, Yulia Fomenko, Darya Pishchalnikova and Gulfiya Khanafeyeva - were bound for the Beijing Olympics.
The other two athletes are Svetlana Cherkasova and Olga Yegorova.
Romania have dropped Elena Antoci and Cristina Vasiloiu from their Olympic team because of suspicion of doping.
The pair are both 1500m runners and they follow in the footsteps of fellow 1500m competitor Liliana Popescu, who was dropped from the country's Olympic team under similar circumstances earlier this month.
Russian Yegorova was booed on her way to claiming the 5,000m title at the World Championships in Edmonton in 2001.
She had tested positive for EPO but had been reinstated in the event on a technicality concerning the drugs test.
Before the heats for the women's 5,000m Paula Radcliffe and Great Britain team-mate Hayley Tullett held up a sign in the stands reading "EPO cheats out".
"These rule violations were established following the deliberate storage of samples by the IAAF and re-analysis using comparative DNA techniques"Soboleva - the reigning 1500m world indoor champion - is the world leader over 800m and 1500m this year, while Tomashova was world champion in 2003 and 2005 and claimed silver at the Athens Olympics four years ago.
Fomenko finished second behind Soboleva over 1500m at the world indoor championships in Valencia earlier this year.
The two field-eventers are also of pedigree, with Pishchalnikova the reigning European discus champion and hammer thrower Khanafeyeva a former world record holder.
The seven have been charged under IAAF rules for a "fraudulent substitution of urine which is both a prohibited method and also a form of tampering with the doping control process", according to a statement from the world governing body.
The statement continued: "These rule violations were established following the deliberate storage of samples by the IAAF and re-analysis using comparative DNA techniques."
The IAAF added the suspensions were "the result of a specific investigation which was instigated and carried out by the IAAF for more than a year".
And the statement concluded: "The IAAF will make no further comment until a final decision has been taken by the ARAF (All Russia Athletics Federation), which now takes over the responsibility to adjudicate these cases."
The athletes have up to 14 days to request a hearing with the national member federation.
If a hearing is requested, it must be held within a period of two months.
The Beijing Olympics athletics schedule is set to get under way on Friday, 15 August.
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