London Marathon organisers have assessed risks following this week’s Boston bombs London Marathon organisers announced on Thursday that they will donate £2 ($3) for every finisher in Sunday's race to a fund for victims of the bomb attacks in Boston.The One Fund Boston was set up to help people affected by the twin bombings that killed three people and injured over 180 during Monday's Boston Marathon.
With around 35,500 people expected to complete the London race, organisers hope to raise more than £70,000 ($100,000) for the fund.
"Everyone connected with the London Marathon was shocked by the terrible events in Boston, and we are keen to show our support to the victims' families and our friends in the running community there," said London Marathon race director Hugh Brasher.
The race director of the Boston Marathon, Tom Grilk, expressed his gratitude for the gesture.
"It was the City of Boston that was attacked this week, and we are deeply gratified that the citizens of Boston are receiving so many displays of support," he said.
"We will remember what the runners in London and the organisers of the Virgin London Marathon are doing on Sunday. On behalf of everyone, thank-you."
There will be a 30-second period of silence prior to the London Marathon in tribute to the Boston victims, while competitors have also been encouraged to wear black ribbons.
A beefed-up police presence for Sunday's event will remain in place despite the death and capture of the Boston Marathon bombing suspects, Scotland Yard said.
London's Metropolitan Police is putting 40 percent more officers along the route than it did last year, to reinforce security and in a bid to reassure the 36,000 runners and tens of thousands of spectators.
Several hundred more officers, plus search dogs, will be deployed this year.
Runners have been encouraged to wear black ribbons and organisers have announced that £2 ($3) for every finisher will be donated to a fund for victims of the Boston attacks.
A 30-second silence will be held ahead of the elite men's race start.
London Marathon chief executive Nick Bitel said Saturday there would still be a "carnival atmosphere" around the course despite the heightened police presence.
"After the terrible events in Boston we conducted a security review with the Metropolitan Police and all the other agencies," he told BBC radio.
"We have increased substantially the number of police officers who are going to be out there, going to be visibly reassuring people and putting in more search regimes and a number of other measures to ensure that it is as safe and fun as it always is.
"I think people will come out and cheer and have a great day."
The London course snakes alongside the River Thames and passes iconic landmarks including Tower Bridge, the Houses of Parliament and Buckingham Palace.
US police on Friday captured a young, ethnic Chechen man suspected of staging the Boston Marathon bombings, after a desperate manhunt that virtually paralysed the city and its suburbs.
Responding to a tip from a local resident, police found Dzhokhar Tsarnaev, aged 19, hiding in a boat in a suburban backyard in Watertown, wounded and weary after a gun battle overnight in which his accomplice brother was killed.