The TV4 reporter, Jens B Nordström, was trying to pass a banana to the prime minister when the confusion occurred.
"The whole thing reminded me of that scene in that Mr Bean movie where he's in an airport and everyone thinks he has a gun, even though he's completely unarmed," Nordström told The Local.
Reinfeldt's bodyguards, however, were taking the matter seriously. After spying the suspicious yellow object, the agents prepared to pounce on the journalist believing the tropical fruit was in fact a weapon.
Nordström was offering the banana to the prime minister after a scientist had mentioned that the fruit can induce doziness after long periods without sleep. With the prime minister having recently battled through mammoth 25-hour sessions at the EU summit, the reporter had just the medicine.
"I told him I had a 'secret weapon', and fumbled around in my pocket and whipped out the banana. I told him he could give it to Angela Merkel so she would get drowsy and go along with his demands," he added with a laugh.
"But the prime minister declined my banana."
The incident occurred during the Husby unrest in Stockholm, and Nordström admitted that it was good to know the agents were "awake and alert".
The reporter has had mixed reactions to the stunt.
"Almost everyone has said that they think it's funny, but some have also made comments saying I'm absolutely insane," he told The Local.
"But when you get comfortable with interviewing people like Fredrik Reinfeldt, you can relax a bit and sometimes it means you do something quirky without realizing."