Sports minister Hugh Robertson insisted he was "absolutely confident" that the London Marathon could be kept safe.
Asked if he believed it should still go ahead, he told the BBC Radio 4 Today programme: "Yes, I do.
"These are balance of judgements but we are absolutely confident here that we can keep the event safe and secure.
"I think this is one of those incidents where the best way to show solidarity with Boston is to continue and send a very clear message to those responsible."
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