Boston - Hundreds of people were evacuated in the US city of Boston on Tuesday after two backpacks were found at the scene of twin bombings that killed three people exactly a year ago.

The Boston Police Department wrote on its official Twitter account that a male suspect had been taken into custody in connection with the unattended backpacks.

The bomb squad was in the area of the finish line of the city's marathon, which this year takes place next Monday, investigating a call about luggage left behind.

A witness told AFP that a young man in his 20s, dressed in black and wearing a backpack, was being questioned by police in the north-eastern city.

The suspect insisted that he was a university student at the Massachusetts College of Art and Design, according to the witness.

Boston earlier paid solemn tribute to the victims and survivors of the April 15, 2013, marathon bombings, observing a moment of silence and raising the US flag exactly one year after the attacks. - Sapa-AFP