By Brian Oliver

LONDON (Reuters) - Russia's weightlifters face being banned from the Rio Olympics, subject to confirmation by the International Olympic Committee, in another collective doping punishment to hit the country.

Five days after its track and field team's suspension from the 2016 Games was upheld, Russia's weightlifters are now also set to be suspended from the August 5-21 Olympics.

Belarus and weightlifting superpower Kazakhstan were also banned over failed retests from the 2008 and 2012 Olympics on Wednesday by the sport's governing body, the International Weightlifting Federation (IWF), which also punished other nations by reducing the number of available athlete slots in Rio.

Retrospective doping tests carried out by the IOC have led to 17 positives from 2008 and 2012, said the IWF. The governing body added there may be more cases to come.

The IWF is awaiting confirmation of those failures and a final tally from the IOC, who were not immediately available when contacted late on Wednesday by Reuters.

Earlier this week the IOC supported the IAAF's decision to continue its ban on all Russian track and field athletes as a collective punishment for the country's systematic doping problems, saying that such a decision was for each sport's federation.

Because of those results, and an unprecedented 24 positives at the weightlifting world championships in Houston, Texas, last November, a special meeting was called for this week in Tbilisi, host of this weekend's youth world championships.

The IWF, stressing its “zero tolerance” toward dopers, said it had taken 11 places away from teams who had committed four or more doping offences in 2015. Two of those teams were Russia and Kazakhstan, so the sanctions could yet be overtaken by a team ban. The others were Azerbaijan, North Korea and Moldova (two places each) and Belarus (one).

As for the banning of entire teams, the IWF said in a statement: “The IWF Executive Board has decided that national federations confirmed to have produced three or more anti-doping rule violations in the combined re-analysis process of the 2008 and 2012 Olympic Games shall be suspended for one year.

"Countries thus subject to suspension are Kazakhstan, Russia and Belarus."

Because the tests were not carried out by the IWF, the sport's administrators are seeking formal confirmation from the IOC that the positives are not subject to appeal or amendment.

The executive board also castigated the European Weightlifting Federation for its recent appointment of Sergey Systsov, president of the Russian Federation, as chair of its anti-doping commission.

"Given the current environment, the IWF Executive Board strongly suggests that Mr Syrtsov and the European Weightlifting Federation reconsiders the appointment,” said a statement.

The IWF has set up an independent commission to investigate the nations who returned three or more positives from the retesting of 2008 and 2012 samples, which was carried out after advances in science enabled better detection of prohibited substances.

The worst offender was Kazakhstan. Ilya Ilyin, the world’s most popular weightlifter, is expected to lose his gold medals from Beijing and London, while three Kazakh women who won in 2012 also tested positive.

The IWF also vowed to toughen its anti-doping policy in future, threatening to ban nations who had the worst doping record during an Olympic qualifying period. It also said it would set up a task force and aimed to test every athlete, before the Games, who will be competing in Rio.

The Olympic bans take to four the number of nations who will not be allowed to compete in Rio. Bulgaria had been excluded last year, after 11 lifters at a training camp tested positive. Romania and Uzbekistan had already lost one quota place each.

(Additional reporting by Mitch Phillips/Karolos Grohmann, editing by Pritha Sarkar)