Track and field's world governing body has admitted that "suspicious delays" by its top anti-doping official allowed four Russian athletes to compete at the 2012 London Olympics when they should have been suspended, including one race walker who went on to win a silver medal.

The IAAF agreed with charges previously leveled in a report by a commission of the World Anti-Doping Agency that the four Russians cases were unreasonably delayed, but denied that there was any wrongdoing in four more cases, including those of two Olympic gold medallists.

In a lengthy statement sent by the IAAF to WADA on Friday and released Monday, the IAAF blamed its former anti-doping director, Gabriel Dolle, saying he held up doping cases against the athletes long enough to let them race at the Olympics.

Dolle received a five-year ban last week from the ethics commission of the International Association of Athletics Federation in connection with alleged extortion and bribery to cover up a Russian doping case. He is also under criminal investigation in France into alleged corruption at the IAAF.

Russia serving suspension

The IAAF's admission comes while Russia is suspended from global track and field following allegations by the WADA panel in November that the country ran a state-sponsored doping program.

All of the eight cases referred to in the IAAF statement result from the biological passport program, where athletes' blood is tested over a long period for evidence of doping. In all four cases, Dolle did not send the required paperwork to allow disciplinary proceedings to start before the Olympics, the IAAF said.

The IAAF acknowledged the delays in the cases of the following athletes:

  • Olga Kaniskina, who won the silver medal in the women's 20-kilometre walk in London. The IAAF said an expert panel ruled she should be suspended a month before the games began. Kaniskina was banned in January 2015 and could lose her medal in an ongoing legal battle.
  • Liliya Shobukhova, who was alleged to have been extorted out of hundreds of thousands of dollars to avoid a doping ban before the Olympics. Her case forms the basis of an ongoing French criminal investigation. A three-time Chicago Marathon winner, Shobukhova raced in London but did not finish. She also finished fourth at the 2012 Chicago Marathon before being banned.
  • Vladimir Kanaykin, who competed at the Olympics but was disqualified for a technical violation in the men's 20km walk while in medal contention. He was banned for life in January 2015.
  • Valery Borchin, who competed at the Olympics as the reigning champion in the men's 20km walk but failed to finish the race. He was banned for eight years in January 2015.

IAAF denies wrongdoing in 4 cases

The IAAF denied wrongdoing in four other cases that the WADA commission had said involved unreasonable delays, including one involving Sergei Kirdyapkin, who went on to win the gold medal in the men's 50km walk, and Turkish athlete Asli Cakir Alptekin, who won the women's 1,500-metre race.

In those cases, the IAAF said the delays resulted from lengthy testing procedures and the need to gather enough evidence of doping over an extended period to convince a tribunal that the blood data gathered was enough to suspend the athletes.

Both Kirdyapkin and Alptekin have since been banned. Alptekin agreed to give up her Olympic title when she was handed an eight-year ban in August, while the IAAF is trying to disqualify Kirdyapkin from his Olympic win in a case before the Court of Arbitration for Sport.

Another of the four, former world walking champion Sergei Bakulin, was banned last year, while the final athlete, Yevgenia Zolotova, is not suspended but stopped racing in June 2012, the IAAF said.

Taskforce visiting Russia to evaluate progress

The IAAF also alleged that Russia tried to enter four athletes for the world championships in Moscow in 2013 when they should have been suspended. However, none of the four actually competed after an unidentified IAAF staff member confronted then-IAAF president Lamine Diack and threatened to resign if the Russians were allowed to race, the IAAF said.

Diack is now a suspect in a French criminal investigation into alleged extortion of athletes to avoid doping bans. His son, former marketing official Papa Massata Diack, was banned for life by the IAAF last week.

Also Monday, an IAAF taskforce visited Moscow for the first time as part of its mission to assess whether Russia is doing enough to reform its anti-doping measures, and eventually pave the way for Russia to return to world athletics.

The IAAF taskforce, led by Norwegian anti-doping expert Rune Andersen, held the first of two days of meetings in Moscow with a Russian delegation.

"Discussions at today's meeting have been frank and open, and we look forward to continuing them with the ICC tomorrow," Andersen said in a statement on the IAAF website.