Speaking after a meeting of the International Association of Athletics Federations' ruling Council, Coe said obstacles had continued to be put in the path of the Taskforce appointed to oversee the transformation of Russia's anti-doping operation.
"There has been some progress but there are still some very big gaps in the key milestones," the IAAF president told reporters. "I'm disappointed and see no reason why better progress has not been made, it's not that complicated frankly.
"Council was disappointed and concerned to learn that the prospect of the milestones being fulfilled this year by RUSAF (the Russian athletics federation) remains a distant one."
Coe identified problems around the number of doping tests, Athlete Biological Passport (ABP) records being withheld, some athletes still training in 'closed cities' with no access for doping control and coaches tainted by the previous regime still operating.
"RUSAF should be under no illusions that the criteria stands," he said.
"We will continue to be tough. There is no timeline here. We will look again in July and make a judgement, but we are going to see this through, this is non-negotiable."
RUSAF was banned in November, 2015 after an independent World Anti-Doping Agency (WADA) probe exposed state-sponsored doping on a massive scale.
Most Russian athletes missed last year's Rio Olympics and will also be absent from August's world athletics' championships in London - with just a handful cleared to compete under a neutral flag.
With such little progress being made and senior officials in Russian athletics and government continuing to rail against what they say is unfair targeting of their country, a return to international competition seems as far away as ever.
The IAAF Council had discussed the latest findings of Rune Anderson, head of the Taskforce, whose lengthy report made depressing reading for anyone hoping to see a zeal for reform.
"The six milestones are still outstanding and at present it does not look like they will be met any time soon," Anderson wrote in his report presented to the Council on Thursday.
Anderson said that RUSAF president Dimitri Shlyakhtin and Russia’s minister for sport Pavel Kolobkov were unhappy that the athletes cleared to compete under the special dispensation rules had to do so as neutrals, rather than representing Russia.
Observing that the matter was one for the IAAF Council to consider, Anderson added that the Taskforce was strongly against such a change.
"It is the loss of the right to enter international competitions that gives the sanction of suspension its weight and its deterrent effect," he said.
"If the athletes are to participate in international competition in their national colours then, in the view of the Taskforce, much of the force of that sanction would be lost."
Coe also made a special mention of Andrey Dmitriev, a Russian athlete who has recently had to flee the country after saying he had been threatened with imprisonment after revealing that tainted coaches were still working in the Russian system.
"The situation surrounding Andrey Dmitriev, a champion of the clean sport movement in Russia, is alarming considering he has felt it necessary to take sanctuary abroad," Coe said.
"Anyone with information about a system which has failed to protect the goals and aspirations of clean athletes must feel it is safe to speak out." (Editing by Ken Ferris)
Read the original article on Eurosport: Sebastian Coe disappointed by lack of Russia doping progress