London - IAAF chief Lord Sebastian Coe believes Russia is showing a significant change in its attitude to tackling the doping scandal that saw the nation exiled from world athletics.
Russia has been banned from international athletics competition since November 2015 after doping issues.
The country's anti-doping agency, RUSADA, is also yet to be declared fully compliant by the World Anti-Doping Agency.
Russian athletes have also effectively been banned from next year's Winter Olympics in Pyeongchang, unless they can satisfy stringent drug-testing regulations in order to compete as neutrals.
Coe indicated there are reasons for hope that Russia is finally dealing with the problem, but he said the IAAF would still resist setting any time-scale for the nation's reintegration into athletics.
"We made a decision that in a way was quite different to the one the IOC was confronted with," Coe told BBC Radio Five Live on Sunday.
"I've had 149 or 150 positive tests in the sport, from Russia within a three or four year period.
"It was very clear as far I was concerned and the Council of the IAAF was concerned that nobody else was going to come to our rescue here. We had to take the appropriate action.
"We set up the task force which created the five-step criteria by which they would be judged - and actually they're moving in the right direction and we've got some significant change.
"The task force reports back to the Council once or twice a year and each time they come back and say there's still more to do.
"But some of the challenges that we were being appraised of just a few months earlier have actually moved.
"I am faithful to the independent work of the task force and the task force will recommend to the council when that moment of reintegration is."