Russia is expected to miss Monday's deadline to hand over data from its anti-doping laboratory in Moscow, increasing the pressure on the World Anti-Doping Agency to reinstate a ban on the country's athletes.
WADA in September lifted its suspension of the Russian Anti-Doping Agency (RUSADA), which was imposed in November 2015, pending the meeting of conditions in a 'roadmap to compliance'. The controversial move upset athletes and athlete groups.
One of the conditions was to allow independent access to the raw data held at the Moscow lab, but WADA on December 21 admitted it had been unable to "complete its mission".
The lab is sealed for a Russian federal investigation and the five-person independent team, led by Dr Jose Antonio Pascual, was told its equipment to be used for the data extraction was required to be certified under Russian law.
WADA is expected to issue a statement on Tuesday, with the matter likely to go before the independent compliance review committee at its next meeting on January 14. If RUSADA is declared non-compliant, Russian athletes will again be banned from international competition.
Conflicting reports have emerged from within Russia, with sports minister Pavel Kolobkov saying a deal had been reached with WADA.
TASS, Russia's state news agency, on Saturday reported details of a letter from WADA president Craig Reedie to the Russian Sports Ministry, which "specifies options to copy the data from the Moscow Anti-Doping Laboratory".
Kolobkov said in a sports ministry media release, according to TASS: "We support WADA's position: it is in our common interest, as well as in the interests of Russian athletes and all clean athletes, to move forward and rapidly resolve all remaining issues.
"We are currently discussing the date of the next visit."
The state-sponsored use of performance-enhancing drugs by Russians in Olympic and Paralympic sports emerged in independent reports in November 2015 and July and December 2016.
Olympic track cycling gold and silver medallist Callum Skinner is a member of UK Anti-Doping's athlete committee and has been an outspoken critic of WADA's reinstatement of Russia.
He issued a media statement on Sunday, which read: "WADA undermined the trust of the world's athletes and sports fans when it made its controversial and deeply unpopular decision in September to reinstate Russia despite the conditions of the organisation's so-called roadmap not having been met - in short, WADA, the rule-maker, changed its own rules to coach Russia into compliance.
"The world's athlete community - whose very lives and careers depend on WADA's ability to act in their interests - looks, yet again, to be neglected and let down by Reedie's WADA.
"They are waiting on WADA to act in the interest of honest athletes, not in the interest of the cheats as many xnow perceive WADA to be acting."