The World Anti-Doping Agency (WADA) today announced a probe into inconsistencies in laboratory data provided by Russia.

WADA said in Tokyo, it had given Russia three weeks to respond after problems with the data came to light. Russia had handed over thousands of files and samples from its Moscow anti-doping laboratory in January, fulfilling a key condition for its reinstatement by WADA last September.

WADA had previously warned that it would take the “most stringent sanctions” if any of the data was found to have been tampered with.

The revelation opens the door for fresh sanctions against Russia, which was banned from the Pyeongchang 2018 Winter Olympics over doping.

Athletics body, the IAAF,  has also maintained a ban on Russia since November 2015, although many of its athletes are given special dispensation to compete under a neutral banner.

The IAAF is due to re-examine the case for reintegrating Russian athletes ahead of the World Athletics Championships, which start in Doha on Friday.