The head of the World Anti-Doping Agency (WADA) has complained of slow progress by Russian authorities toward making the country's anti-doping agency, RUSADA, compliant with international standards.
WADA officials want to join the Russian committee visiting the Moscow testing laboratory at the heart of what investigators say was widespread state-backed doping.
Giving WADA access to samples sealed in storage by Russia is a key point to reaccrediting RUSADA, which was suspended in 2015 when WADA investigators detailed doping in Russian track-and-field.
WADA chief Craig Reedie told an anti-doping conference in the Swiss city of Lausanne that four letters had gone unanswered and "our offer has fallen on deaf ears."
"We want to welcome an independent and efficient RUSADA back in from the cold...it's just a pity it is taking so long for Russian authorities to make it happen," Reedie said.
There was no immediate response to Reedie's remarks by Russia, which has repeatedly denied systemic doping.
After escaping a total ban from the Rio de Janeiro Olympics in 2016, Russia was barred from last month's Winter Games in Pyeongchang although more than 100 of the country's athletes were permitted to compete as neutrals.
