Three people were killed and more than 100 injured in the blasts. As of Tuesday morning, no one had claimed responsibility for the attacks.
Despite the tragedy, Prince Harry is expected to be at this weekend's race through London.
"We announced last week that Prince Harry would attend this year's London marathon in his capacity as Patron of the London Marathon Charitable Trust and that he would make the presentations to the winners and meet a selection of volunteer and support staff. As things stand we are not aware of any changes to that plan but ultimately we will be directed by the race organizers," a palace spokesman told E! News Tuesday.