Londoners should show their solidarity with victims of the Boston blasts during Sunday's Marathon, according to Britain's Sports Minister Hugh Roberston, after organisers said the iconic race will go ahead as planned.
Security is being scrutinised for the London event, which will attract 36,000 runners, in the wake of Monday's horrific scenes in Boston, where explosions near the finish line killed at least three people and wounded more than 100.
The Boston blasts, which left many people gravely injured, detonated close to spectators standing behind roadside barriers.
"In security terms, we are as confident as we possibly can be that we can deliver a safe and secure marathon"
British Sports Minister, Hugh Roberston
It was the worst bombing on U.S. soil since security was tightened after the attacks of September 11, 2001, and President Barack Obama promised to hunt down whoever was responsible for the attack on a day when tens of thousands of spectators packed the streets to watch the world-famous race.
Britain's double Olympic champion Mo Farah is set to compete in the 41.84 kilometres London race on Sunday, which starts at Greenwich Park and winds through some of the city's iconic landmarks before finishing at the Mall.
Robertson said he was confident of security arrangements for the London event and encouraged people to attend as a show of solidarity with Boston.
"In security terms, we are as confident as we possibly can be that we can deliver a safe and secure marathon," Robertson said in an interview on the BBC and Sky TV.
"We deliver major events in London, if not quite on a daily basis, on a weekly basis," he said.
"We have enormous experience of doing this, and we have some of the very best professionals anywhere in the world, if not the best professionals in (London's) Metropolitan Police, our security services and our armed forces to do this.
"The best way of dealing with this is to get out on the streets, is to show solidarity with the people in Boston, to celebrate a fantastic marathon and send out a very clear message to those responsible that we won't be cowed by this kind of behaviour."
The Metropolitan Police, who will also mount a large security operation for the funeral of former Prime Minister Margaret Thatcher on Wednesday, said it was liaising with race organisers.
"We will be reviewing our security arrangements in partnership with the London Marathon," Metropolitan Police chief Superintendent Julia Pendry said in a statement.
The London race was first run in 1981 and has become a centrepiece of the sporting calendar in Britain with elite athletes being joined by the vast number of amateur runners who compete to raise money for charity.
Hundreds of thousands of people line the course with music and food stalls adding to the party atmosphere.
"We are deeply saddened and shocked by the news from Boston," London Marathon Chief Executive Nick Bitel said.
"Our immediate thoughts are with the people there and their families. It is a very sad day for athletics and for our friends and colleagues in marathon running," Bitel said.
"Our security plan is developed jointly with the Metropolitan Police and we were in contact with them as soon as we heard the news."
The U.S. Federal Bureau of Investigation has taken the lead on the investigation with help from several other U.S. federal, state and local law enforcement agencies.
The two explosions at 1850 GMT were about 50 to 100 metres apart as runners crossed the finish line with a timer showing four hours and nine minutes, some nine minutes faster than the average finish time, as reported by Runner's World Magazine.