Boston police took one man into custody and detonated the two backpacks after they were found unattended on Boylston Street. Police said the backpacks were detonated "for precautionary reasons."
At least one of the bags was being carried by a barefoot man who was wearing a long black veil and screaming "Boston Strong." That man has been identified as 25-year-old Kayvon Edson, CBS News reported.
When Edson was stopped by police, he told them he had a rice cooker in his bag. That is when the Bomb Squad was called to the scene, a source was quoted by WBZ-TV as saying.
The rice cooker in the bag was full of confetti, another source said.
Edson is charged with disorderly conduct, disturbing the peace, and possession of a hoax device.
Before the detonations, police ordered an evacuation of the area near the finish line and the police bomb squad arrived at the scene, the Boston Globe reported.
The loud booms near the finish line, a year to the day after the deadly 2013 Marathon bombings, frightened dozens of bystanders.
Shortly before the detonation, an officer guarding the scene got into a heated exchange with a man who wanted to cross the police tape to get to his residence.
"There's a bomb down the street," the officer shouted to the man. "Do you understand that?"
Earlier in the day, survivors of last year's bombings joined rescuers, public officials, and others for a ceremony at the nearby Hynes Convention Centre.
One year ago, three people died, and more than 260 people were injured when two bombs exploded near the finish line of the marathon.
Two brothers who were ethnic Chechens planned and orchestrated the twin bombings near the marathon finish line.
Tamerlan Tsarnaev, 26 died following a shootout with police several days after the bombings while his brother Dzhokhar Tsarnaev, 20, has pleaded not guilty to 30 federal charges and is awaiting a trial.
This year, the Boston Marathon -- which has been run since 1897 -- will take place on April 21.
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