U.S. Vice President Joe Biden says the one-year anniversary of the deadly bombings at the Boston Marathon is not just an important day for survivors, but an important day for the entire United States.
The two bombs, which authorities say were planted near the marathon finish line by ethnic Chechen brothers Tamerlan and Dzhokhar Tsarnaev, killed three people and wounded more than 250 others.
Speaking Tuesday in Boston at an anniversary ceremony, Biden called the survivors of the attack "living proof" America can "never be defeated." And he had a similar message for those planning to run the 2014 race.
"And next Monday , on Patriot's Day, when I am told up to 36,000 people line up to start the marathon, you will send a resounding message around the world - not just to the rest of the world, but to the terrorists - that we will never yield, we will never cower. America will never, ever, ever stand down. We are Boston. We are America. We respond, we endure, we overcome and we own the finish line."
Boston Mayor Martin Walsh and Massachusetts Governor Deval Patrick also took part in the tribute, along with survivors of the blasts, victims' families and medical staff.
Authorities say the Tsarnaev brothers carried out the attack using homemade bombs.
The attack set off a multi-day manhunt that ended with Tamerlan Tsarnaev dead from a shootout with police and a bloody Dzhokhar being arrested in a Boston suburb.
Dzhokhar is due to go on trial in November on 30 federal charges and will face the death penalty.
The Boston Marathon is one of the most prestigious in the world, and has been held every year since 1897.
This year's race features an expanded field of runners, about 9,000 more than in 2013. The field includes several thousand runners who started last year's race, but were unable to finish because of the bombings.
Organizers have boosted security, with cameras installed along the route and thousands of police and hundreds of National Guard troops set to be deployed in the area.