Updated

Players from Russia's under-21 national soccer team had suspicious drug-test samples covered up, emails released by a World Anti-Doping Agency investigation show.

The emails, released this month as part of WADA investigator Richard McLaren's report on Russian doping, state that there were five suspicious samples in the Russian men's under-17 and under-21 national teams in 2013 and 2014.

Another case in the Russian league was allegedly covered up by then-Sports Minister Vitaly Mutko, who is also in charge of the country's World Cup preparations. The FIFA ethics committee is holding a preliminary investigation into the McLaren report and the role of Mutko, who sits on the FIFA Council.

The allegations follow a tough year for Russian soccer, which is trying to prepare to host the 2018 World Cup but has faced criticism over hooliganism involving fans at the European Championship and racism in the domestic game.

The doping cases in the Russian national teams were all recorded as clean by Moscow lab director Grigory Rodchenkov after instructions from Sports Ministry employee Alexei Velikodny to "save" the players, McLaren's investigation found.

The records show that three members of the Russian under-21 team gave suspicious samples at the national training base shortly before traveling to the 2013 European championship, with two showing elevated testosterone levels — a key indicator of doping — and another testing positive for cannabis. A fourth player's sample contained high traces of alcohol, which isn't banned but seems to have been included in the documents as a warning.

Rodchenkov and Velikodny discussed the players by name in emails, in breach of confidentiality rules, and Velikodny instructed the lab director to take no further action.

It is not clear which players gave the suspicious samples, since their names have been redacted. The Russian squad at the tournament included some players who have gone on to play for Russia's national team.

At least two other international tournaments were affected in 2014. A player from a leading Russian club gave a sample with a "huge" cannabis reading ahead of Russia's European under-21 qualifier against Estonia, prompting Rodchenkov to comment that "he needs to be chased out of the team," though no positive was recorded. A player from Russia's under-17 team tested positive for arimistane ahead of qualifiers against Spain and Switzerland.

There are also two recorded cases in the Russian league. In one case, an unknown player tested positive for dexamethasone, an anti-inflammatory steroid with various uses including legitimate medical purposes. In the other, a player from another former Soviet country tested positive for the banned peptide hormone hexarelin.

McLaren said the hexarelin case was covered up on the order of Mutko, who is now deputy prime minister. That allegation rests on a comment by Rodchenkov that it was "the decision of VL," the initials of Mutko's first two names. Other people in the emails are referred to using initials in a similar way.

"FIFA is now reviewing the evidence provided by WADA after the final McLaren report, and based on this information FIFA will take the appropriate next steps in accordance with the anti-doping regulations," the governing body said. "The result of the investigation will be communicated in due course. Please understand we cannot comment further at this stage."

Both UEFA and the Russian Football Union, of which Mutko is president, declined to comment.