Germany head coach Joachim Low has called for clarity in the controversy over doping allegations levelled at Russia's 2014 World Cup squad.
A report in the Mail on Sunday claimed that Russia's 23-man squad at the finals in Brazil, along with another 11 footballers, are "people of interest" to officials at the heart of the probe into state-sponsored doping in Russia.
FIFA is "still investigating" the claims, which relate to players mentioned in the McLaren Report, which last year claimed more than 1,000 Russian sportspeople benefitted from a highly organised state-doping scheme, described as corruption "on an unprecedented scale" that led to a ban on Russian athletes competing at the Rio Olympics.
Both FIFA and Russian officials have pointed out none of their players have failed doping tests over recent years, with Russia 2018 chief executive Alexey Sorokin labelling the Mail's allegations as "bizarre" and "made-up"
However, Germany television network ARD conducted an interview with McLaren, where the World Anti-Doping Agency investigator said 155 samples related to Russian footballers had been reported to FIFA and that he suspected foul play.
"There are 155 samples that were seized by WADA and are awaiting analysis. We have reported those to FIFA," McLaren said.
"Either there's been tampering with the caps so that contents could have been changed, or the contents haven't been changed but there may be prohibited substances in there.
"That gives rise to a suspicion that there is a bank of clean samples and that it's been used with respect to footballers."
Picking through an increasingly confused situation of claim and counter-claim, Low called for the authorities - both FIFA and WADA - and the media to name doping offenders as soon as proof is to hand.
"This investigation is still on-going and I don't want to stoke any of these speculations," he told a news conference ahead of Germany's Confederations Cup semi-final against Mexico in Sochi.
"I cannot assess the situation. I have heard of it and, if that [there has been doping], I would like to have the names.
"Please print the names in newspapers, give the names in public and that would mean we should proceed where WADA or FIFA or any organisations conducting those doping tests just call a spade a spade. Then we know what's going to happen from there.
"Always keeping the speculations simmering and coming up with another set of allegations that so and so are there... I can't prove it and no one apparently can if we do not have the facts here on the table, and I don't want to assume that others do."
Low also called for swift action to be taken against any players found to have been doping.
He added: "Now, those organisations that are permanently testing us in our training camps and before and after the games, I want to have the names, please.
"If there really are the names there, they shouldn't be hidden at all. If there is something to it, make it public and if players have been doped they have to be removed. They have to be suspended."