The world governing body of athletics on Sunday maintained its suspension of Russia, saying the country still had not done enough to clamp down on doping.
Rune Andersen, the head of the International Association of Athletics Federations (IAAF)'s anti-doping Task Force, said "several key (milestones) remain outstanding" before the necessary conditions for Russia's return could be met.
Russia was banned from international athletics in November 2015 over claims of state-sponsored doping, preventing its athletes from competing at the 2016 Rio Olympics and this year's World Championships in London.
Andersen said that until the World Anti-Doping Agency (Wada) reinstated Russia's domestic anti-doping agency RUSADA, the IAAF could not allow the country's athletes back into international competition.
Wada ruled in mid-November that Russia was still not compliant with international rules on doping.
'STILL NO ACKNOWLEDGEMENT'
At a press conference during the IAAF Council in Monaco, Andersen said the "reinstatement of RUSADA as a fully independent and code-compliant" body was a key condition for Russian athletes to return to athletics.
The Norwegian official added that Russian authorities were still reluctant to accept that they had covered up evidence of doping.
"Unless there is an acknowledgement of what happened before, there can be no assurance that it will not happen again," Rune added.
IAAF President Sebastian Coe said he accepted Russia was not ready to return, despite expressing optimism in an interview with AFP in October that Russian authorities were moving in the right direction.
"We have unanimously, on every occasion, endorsed the recommendations of the Task Force, and we will continue to do that," Coe said.
The IAAF decision comes ahead of a crucial International Olympic Committee (IOC) meeting on 5-7 December on whether Russia can compete at the 2018 Winter Olympics in Pyeongchang, South Korea.
On Friday, the IOC annulled the titles that Russia's Alexander Zubkov won in the two-man and four-man bobsleigh at the 2014 Russian-hosted Sochi Winter Olympics following hearings by its commission into state-sponsored doping.
That followed punishments announced Wednesday for four Russian skeleton competitors.
Russian sports officials responded to that decision by saying they were prepared to take legal action against the IOC.
A rush of rulings this week means that, in total, the IOC has punished 14 Russian Olympians on the recommendation of a commission headed by Swiss sports official Denis Oswald set up to investigate evidence of doping with state involvement.
Russia has lost nine medals, including four of its 13 golds, from the Sochi Games they hosted.
Russia's former world champion sprint hurdler Sergey Shubenkov was one of the Russian athletes who had to compete as a neutral at the athletics World Championships in London because of the ban on his country.
He said there should not be a "blanket ban" for Russia's Winter Olympians.
"Everybody who is not involved in the scandal should be allowed to compete wearing their national colours," he told the BBC.