Well in light of the Iran-Contra scandal, the former Iran Foreign Minister statement might have an element of truth to it.
Reagan claimed he had no direct knowledge in the arms-for-hostages Iran-Contra scandal and it's creditable he had no direct knowledge in the arms-for-not-freeing-hostages claim during the Iran hostage event.
Then there is William Casey, the then campaign manager, later CIA Chief under Reagan where there is creditably evidence of his involvement.
Sadegh Ghotbzadeh - Wikipedia, the free encyclopedia
"He was "quoted by Agence France Presse saying that he had information that presidential candidate Ronald Reagan was `trying to block a solution` to the hostage crisis. ... Two friends of Ghotbzadeh who spoke to him frequently during this period said that he insisted repeatedly that the Republicans were in contact with elements in Iran to try to block a hostage release."