Russia is at the centre of another doping scandal after it emerged the country’s entire 23-man squad from the 2014 World Cup is being investigated by Fifa over possible drugs offences. Russia is currently hosting the Confederations Cup and in under a year will stage the World Cup but these allegations are likely to throw its suitability to stage such events into serious doubt.

The 23-man squad, who were knocked out in the group stages of the Brazil World Cup three years ago, are among 34 Russian footballers being investigated by football’s world governing body. Five of the 23 players tested in 2014 are members of the squad that was knocked out of the Confederations Cup on Saturday.

The state-sponsored doping and cover-up in Russia are well known but this is the first time top-level footballers in the country have been placed under investigation, although there is no proof of any anti-doping violations. However, a report by the Mail On Sunday alleged the footballers were among 1,000 “people of interest” to the officials charged with establishing where the tentacles of Russia’s doping racket extended.

A Fifa spokesman told the Mail On Sunday: “Fifa is still investigating the allegations made against [Russian] football players.”

It is understood Fifa is in possession of detailed evidence and intelligence. It is likely to face pressure to act on whatever evidence it has. Dick Pound, a former head of the World Anti-Doping Agency (Wada), told the Mail On Sunday: “There is a huge onus on Fifa to reach a sensible conclusion on these matters before the World Cup takes place. It is incumbent on them to say what steps they are taking, what they find, and take whatever action necessary to protect the integrity of sport. Even within a governing body with as little credibility remaining as Fifa, if you were a senior official you wouldn’t want to be part of a body that ignores this.

“There has been an institutional denial of doping in football for years … I’ve seen too many presentations by Fifa, straight out of fantasy land, about how they don’t have a problem. They absolutely have to take this case seriously.”

The new allegations follow the publication of two reports commissioned by Wada and authored by the Canadian lawyer Richard McLaren. It found at least 1,000 people were assisted by what McLaren described as an “institutionalised manipulation of the doping control process in Russia”.

More than 200 of those are thought to have competed in athletics with 13 other sports having competitors in at least double figures being implicated and several cases in other sports.