The New York Times / Robbie Brown

ATLANTA — A Florida man was charged with plotting a terrorist spree around Tampa, including bombing nightclubs, destroying bridges and shooting police officers in the name of radical Islam, federal authorities said Monday.

The man, Sami Osmakac, 25, an American citizen born in the former Yugoslavia, planned to use firearms and explosives that he had bought from an undercover F.B.I. agent, the authorities said. He was arrested Saturday after months of surveillance by the F.B.I.

Shortly before his arrest, Mr. Osmakac made a video of himself, seated cross-legged on the floor with a pistol in his hand and an AK-47 behind him. He said he was willing to die to avenge Muslim deaths.

“We all have to die. So why not die the Islamic way?” he asked, according to a 14-page complaint released by the United States attorney’s office in Tampa.

Authorities did not indicate whether Mr. Osmakac had acted in collaboration with any terrorist group.

Surveillance of Mr. Osmakac began after the authorities received a phone call in September from an unidentified informer. Mr. Osmakac had come into the informer’s store, trying to buy an Al Qaeda flag, and then began working at the store.

According to the complaint, Mr. Osmakac asked the informer for help getting firearms and explosives, and the source put him in touch with an undercover F.B.I. agent. The authorities said that in recorded conversations with the agent, Mr. Osmakac said he wanted to buy an AK-47-style machine gun, Uzi submachine guns, high capacity magazines, grenades and an explosive belt.

Later, Mr. Osmakac allegedly put $500 as a down payment on the items, which had been rendered inoperable by law enforcement. He told the agent he wanted to strike locations that were “real busy,” detonating car bombs and destroying a bridge between Tampa and Pinellas County, Fla.

His targets, he is accused of saying, were the “kuffar” — an Arabic word for infidels or disbelievers of Islam

“I want to do something terrifying,” he said, according to the affidavit. “Like, one day, one night, something’s going to happen, then six hours later, something else.”

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