A man taken into custody near the scene had a rice cooker in his backpack and is being charged with possession of a hoax device, disturbing the peace and disorderly conduct, officers said.
The man was stopped by an officer who saw him acting suspiciously. He says the man dropped the backpack and it was later blown up by the bomb squad as a precaution, as was a second unattended backpack found nearby. Detectives could not confirm what was in the second backpack or who owned it.
The backpacks rattled nerves on the anniversary of the Boston Marathon bombing, in which two pressure cooker bombs in backpacks killed three people.
Survivors, first responders and family members of those killed came together earlier to mark the anniversary of the bombing with solemn ceremonies.
Former mayor Thomas Menino addressed an invitation-only audience of about 2,500 people at the Hynes Convention Centre, not far from the finish line where more than 260 others were killed or wounded a year ago.
“This day will always be hard, but this place will always be strong,” he said.
In Washington, President Barack Obama said: “Today, we recognise the incredible courage and leadership of so many Bostonians in the wake of unspeakable tragedy. And we offer our deepest gratitude to the courageous firefighters, police officers, medical professionals, runners and spectators who, in an instant, displayed the spirit Boston was built on – perseverance, freedom and love.”
Vice president Joe Biden was in Boston for the ceremony, and he said the courage shown by survivors and those who lost loved ones was an inspiration for other Americans dealing with loss and tragedy.