MIAMI -- A man described by the FBI as an Islamic State of Iraq and Syria (ISIS) sympathizer who hoped to mount attacks on U.S. soil was charged Tuesday with plotting to detonate a nail-filled backpack bomb on a Florida beach. A criminal complaint unsealed Tuesday charges 23-year-old Harlem Suarez with attempting to use a weapon of mass destruction in the U.S. Authorities say he came to the FBI's attention through his Facebook posts praising ISIS and containing extremist rhetoric. CBS News' Paula Reid reported that Suarez allegedly planned to carry out an attack around the July 4th holiday, according to court documents. In April, Suarez allegedly posted, "Be a warrior, learn how to cut your enemies head and then burn down the body learn how to be the new future of the world Caliphate" -- a reference the ISIS goal of building a regional fundamentalist entity. The FBI says he later added a request "from any brother. How to make a bomb send me a video or something, what do I need to make it." Suarez made his first court appearance Tuesday and was being held without bail with a detention hearing set for next week. His temporary attorney, Richard Della Fera, said in an email that Suarez "may be a troubled and confused young man but he is certainly not a terrorist." The complaint says Suarez told an FBI informant he wanted to make a timer bomb, bury it on a Key West beach and detonate it remotely. Suarez was arrested Monday after taking possession of an inert explosive device provided by an FBI informant. "I can go to the beach at the night time, put the thing in the sand, cover it up, so the next day I just call and the thing is gonna, is gonna make, a real hard noise from nowhere," Suarez told an FBI source in a recorded call, according to the complaint. Suarez lives with his parents and attended Key West High School but did not graduate, CBS affiliate WFOR in Miami reported. Suarez was being monitored for months by U.S. authorities and never made an actual explosive, and there was no indication in the FBI complaint that he had contact with any ISIS militants overseas. Still, Miami's FBI special agent in charge, George Piro, said the alleged threats had to be taken seriously. Among other things, the FBI says Suarez also sought to make an ISIS recruitment video using a script he wrote himself. It eventually was made under FBI surveillance at a motel, according to the complaint. "American soil is the past, we will destroy America and divide it in two, we will rais(e) our black flag on top of your white house and any president on duty (cut head)," Suarez says in a script for the video. The FBI says Suarez ordered an AK-47 assault rifle on the Internet and intended to have it delivered to a Key West pawn shop. Although he could legally purchase the weapon, the FBI says, Suarez incorrectly filled out paperwork and it was returned to the seller.
It is only a matter of time until an ISIS agent , or activist , carries out a significant raid on US soil . The FBI 's recent belief that ISIS is now its biggest security concern for IS USA was underscored by the charges set against 23 year - old Harlem Suarez yesterday . Suarez was set to hit a Florida beach with a nail - bomb ; another radicalised activist from Boston , recently arrested , was busy practising with pressure cooker bombs .