The London Marathon, registration and all associated events will go ahead as originally planned, organisers said.
Security arrangements will continued to be reviewed in partnership with the Metropolitan Police and other authorities.
– London Marathon Chief Executive Nick Bitel
The support we have been offered by our stakeholders and the wider running community has been outstanding. We have the full support of the Metropolitan Police, the Mayor's office and other authorities.
We want to reassure our runners, spectators, volunteers and everyone connected with the event, that we are doing everything to ensure their safety and that the Virgin London Marathon 2013 is an outstanding success.