(CNN) -- Five suspects, some of whom describe themselves as anarchists, were arrested after allegedly conspiring to blow up a bridge near Cleveland, the FBI said Tuesday.
"The public was never in danger from the explosive devices" because an undercover FBI agent was involved and the explosives were inert, the bureau said in a news release.
"The defendants were closely monitored by law enforcement," it said.
Authorities say three of the men are self-proclaimed anarchists who had considered "a series of evolving plots over several months."
The individuals allegedly conspired to acquire C-4 explosives and build two improvised explosive devices to be remotely detonated, according to the FBI.