A report will drag back Athletic though the mud on Monday that promises to show more IAAF officials allegedly accepted bribes to cover up positive drug tests.
"Here you potentially have a bunch of old men who put a whole lot of extra money in their pockets - through extortion and bribes - but also caused significant changes to actual results and final standings of international athletics competitions.
"This is a whole different scale of corruption than the FIFA scandal."
Speaking on BBC Radio 5's Sportsweek, Coe admitted these were indeed "dark days" for athletics.
"I was in clear shock and a great deal of anger and a lot of sadness [when hearing the news]. These are dark days for our sport but I'm more determined than ever to rebuild the trust in our sport," he said.
"I'm determined to rebuild and repair the sport with my council colleagues - but this is a long road to redemption."
It is latest crisis to hit athletics after French authorities this week placed his long-serving predecessor Lamine Diack under formal investigation on suspicion of corruption and money laundering.
Diack, 82, is alleged to have received more than ￡700,000 fifa coins in bribes in 2011 to cover up positive doping tests of Russian athletes.Diack's family has dismissed what they described as excessive and insignificant accusations.
There has been talk of the possibility of Russia being thrown out of the sport but Coe said: "I believe isolation is not the answer and that engagement is a much better way to get internal change. But I am not saying and never have said, never.
"Will we ever have a clean sport? No. There will always be people in any walk of life who will step beyond the moral boundaries. It is our responsibility to make sure we have the right systems in place - and the right people in the organisation upholding those systems."Coe was also asked if he regretted referring to Diack as the sport's "spiritual leader" when he succeeded him.
"I'm well aware I'm going to come in for criticism for those remarks," said Coe. "Should we, in hindsight, have known more? Yes, probably we should have done - that is why I have accelerated these reforms at breakneck pace this week."
In July, the Daily Express carried an exclusive interview with former British body builder Dorian Yates, who held the highest accolade in the sport - a six-time My Olympia - in the 1990s and who spoke openly about his own performance-enhancing drug use and information that led him to believe the public are naive to think that such substances are not being taken in mainstream sport.
These new allegations against IAAF officials add credence to his views.
"People see these guys on TV and it is all squeaky clean - but it would be so naive to think that if you could take something that would increase your performance by whatever, two per cent, five per cent, 10 per cent, one per cent - even half a per cent - that it is not being used. People could not afford fut 16 coins not to take it," he said.
"But it's not like you are putting a rocket pack on your back in the 200m, you still have to run it, it is still your body, you're just enhancing an aspect of it."