URGENT: A 25-year-old man described as an Islamic extremist was arrested in an alleged plot to attack crowded areas in the Tampa, Fla., area with a car bomb, assault rifle and other explosives, authorities said Monday.
The U.S. Department of Justice said Sami Osmakac, a naturalized U.S. citizen who was born in the former Yugoslavia, was arrested Saturday night.
Osmakac, from Pinellas County, allegedly told an undercover agent that "We all have to die, so why not die the Islamic way?'" according to a federal complaint.
FBI agents arrested Osmakac on Saturday after he allegedly bought explosive devices and firearms from an undercover agent. The firearms and explosives were rendered inoperable by law enforcement. The federal complaint says that shortly before his arrest, Osmakac made a video of himself explaining his motives for carrying out the planned violent attack.
He has been charged with one count of attempted use of a weapon of mass destruction. His first appearance in federal court is scheduled for Monday at 2 p.m. ET.
Sources close to the investigation told Fox News that Osmakac was being "closely monitored by law enforcement" for months in what authorities have described as a "sting operation."
Federal officials said a confidential source told them in Sept. 2011 that Osmakac wanted Al Qaeda flags. Two months later, the federal complaint said, Osmakac and the confidential source "discussed and identified potential targets in Tampa" that Osmakac wanted to attack.
Osmakac allegedly asked the source for help getting the firearms and explosives for the attacks, and the source put him in touch with an undercover FBI employee.
On Dec. 21, Osmakac met with the undercover agent and allegedly told the agent that he wanted to buy an AK-47-style machine gun, Uzi submachine guns, high capacity magazines, grenades and explosive belt. During a later meeting, Osmakac gave the agent a $500 down payment for the items.
"According to the complaint, Osmakac also asked the undercover employee whether he/she could build bombs that could be placed in three different vehicles and detonated remotely, near where Osmakac would conduct a follow-up attack using the other weapons he requested," a press release from the Department of Justice said. "The undercover employee said he/she could possibly provide explosives for one vehicle. Osmakac also allegedly said that he wanted an explosive belt constructed to kill people."
On Jan. 1, Osmakac told the agent that he wanted to bomb night clubs, the Operations Center of the Hillsborough County Sheriff's Office and a business in Tampa, Florida.
Osmakac told the undercover FBI agent that he wanted to detonate a car bomb and use the explosive belt to "get in somewhere where there's a lot of people" and take hostages.
He also allegedly told the agent that "Once I have this…they can take me in five million pieces," in an apparent reference to a suicide blast. During that meeting, the agent told Osmakac he could always change his mind about his plot.
Osmakac had created a "martyrdom video" and tried on a bomb belt before being arrested Saturday, law enforcement officials told Fox News.
Fox News' Mike Levine and the Associated Press contributed to this report.