Extra police will be deployed to monitor security at the London Marathon in the wake of the fatal bombings at the Boston Marathon.
More police will be at the event after two bombs at the Boston Marathon killed three people and left almost 200 others with serious injuries on Monday.
London Marathon chief executive Nick Bitel said that the Mayor of London, Boris Johnson, had emphasised the importance of a visible police presence for the race in the British capital.
"We instigated a full security review. Considerable extra police and our own security resources will be employed," Bitel said.
"The Mayor made it very clear to the Commissioner [of the Metropolitan Police], and the Commissioner down to his staff as well, that it is about putting out the right number to send the right message.
"It is not about budget, it is not about money; it is about ensuring the police are able to do as they do every day and keep London safe and secure."
Last year, more than 37,500 runners completed the London Marathon.
