The World Anti-Doping Agency has opened compliance proceedings against the Russian Anti-Doping Agency (RUSADA) over what it said were inconsistencies in data supplied to WADA in January.
The news means RUSADA is in danger of being declared non-compliant by WADA only months after a suspension was lifted, which could put increased pressure on the International Olympic Committee (IOC) to exclude Russia from the Tokyo Olympics next year for failing to ensure that its athletes are clean.
The WADA Executive Committee received a report from its Compliance Review Committee on Monday updating it on the analysis of data from the Moscow laboratory which contained the results of thousands of anti-doping tests undergone by Russian sportsmen and women.
"The ExCO was informed that further investigation ... of inconsistencies in Moscow Laboratory data had led WADA to open a formal compliance procedure against RUSADA on 17 September 2019," WADA said in statement.
It said 47 cases had been highlighted and were being acted on.
Jonathan Taylor, chair of WADA's Compliance Review Committee, presented the information to the executive committee in Tokyo on Monday.
WADA has been under huge pressure to bring Russia into line since a 2015 report outlined evidence of systematic, state-backed doping in Russian athletics.
That was amplified a year later when a report by Canadian lawyer Richard McLaren revealed doping and testing manipulation in Russia across many sports.
Last September, the WADA executive committee voted to reinstate RUSADA before it had fulfilled the requirements laid out in a "Roadmap to Compliance", which included handing over the data from the Moscow lab.
After the data and samples from the Moscow lab were finally handed over, WADA investigators performed analysis before passing on the information to international sports federations to take measures against the athletes.
Last month, the International Weightlifting Federation provisionally suspended 12 Russian athletes for doping violations based on data from the Moscow laboratory.
The Russian Athletics Federation (Rusaf) remains banned from international competition.
The governing council of the IAAF, athletics' ruling body, meets in Doha on Monday, with the latest report from its Russia task force and possible reinstatement of Rusaf on the agenda.