US President Barack Obama on Tuesday remembered victims of the Boston Marathon bombings, praised people who came to their aid and lauded the "incredible courage" of Boston "to run again" at the anniversary of the tragedy.

In a statement released by the White House, Obama remembered four people killed and hundreds injured in the tragedy and the following manhunt of suspects a year ago and sent thoughts and prayers to those who were still "struggling to recover."

He went on to praise the first responders and spectators who came to their aid following the blasts.

"Today, we recognize 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," Obama said.

"The most vivid images" from that day were not of smoke and chaos, but of "compassion, kindness and strength," he said.

When this year's Boston Marathon takes place next Monday, Obama said, "hundreds of thousands will come together to show the world the meaning of Boston Strong as a city chooses to run again."

The White House is scheduled to hold a moment of silence for the victims of the tragedy on Tuesday afternoon. Vice President Joe Biden will attend a memorial service in Boston.

Two bombs exploded near the finish line of the Boston Marathon on April 15, 2013 that killed 29-year-old Krystle Campbell, eight- year-old Martin Richard and Lingzi Lu, 23, a Chinese graduate student at Boston University. More than 260 people were also injured in the blasts.

MIT Police Officer Sean Collier was also allegedly killed by the bombing suspect in Cambridge that week.