The organisers of the London Marathon have confirmed that runners will be encouraged to wear a black ribbon at the start of Sunday's race to honour victims of the attack on the Boston Marathon.
An email to runners this morning said:
"As a show of solidarity with our Boston friends, we would also like you to wear a black ribbon at Sunday's race.
You will have the opportunity to collect this ribbon when you register at the Expo to pick up your race number."
The email also said that a 30-second silence would observed at all three race starts and would be signalled by a whistle.
Athletes from the South East, caught up in the Boston Marathon bombing, have been describing the terrifying scenes they witnessed. Malcolm Shaw reports.
Darren Foy, 40, from Southampton, his wife Sandra and their two children, missed the explosions by just half an hour after he finished the Boston Marathon in three and a half hours.
The chartered surveyor, who is chairman of the Lordshill Road Runners in Southampton and was competing in his fourth marathon, said: "There are reports here that the explosions came from a hotel at the finish line and I walked past there a few days ago to pick up my race number.
"It's such a soft target. There are hundreds of thousands spectators on the streets and 27,000 runners, so we got off lightly."
More than 30 runners from our region were taking part in yesterday's Boston Marathon.
While some had completed the course when two explosions occurred near the finishing line, many were still running at the time.
Darren Foy, 40, from Southampton and his wife Sandra and their two children missed the explosions by just 30 minutes after he finished the marathon in three and half hours.
He said: "We were on our way home when we heard something had happened and I was getting messages like 'are you Ok?' which I never get. It's all quite shocking really."
Brighton runner Abi Griffiths crossed the finish line of the Boston Marathon around ten minutes before the explosions happened.
She said: "It was as I was retrieving my bag that I heard an explosion, now everyone sort of looked around and there was a moment of disbelief and bewilderment, you didn't exactly know what had happened, but a few seconds after that suddenly it went into a state of chaos.
"The sound of the explosion, the ground shook underneath my feet a bit, I mean, just, I've never heard a bomb before but there was just that sixth sense that something bad had happened."
Former Metropolitan Police Officer Graham Whettone has told Daybreak that security protocols surrounding Margaret Thatcher's funeral will most likely be reviewed in light of what happened at the Boston Marathon.
He said: "If they need to advance [the plans] then they will do, there's different tactical options the police can employ at various events, they will just review those now, if they need to advancer them then they will do."
The total of people injured by blasts at the Boston Marathon has risen to 144 people, officials at Boston area hospitals said to CNN.
At least three people were killed by two blasts at the finish line of the Boston Marathon, police confirmed.
Doctors said that many of the injured who were admitted to hospital had severe leg injuries caused by shrapnel, and confirmed at least 10 amputations.
The UK Consulate in Boston has tweeted contact information for anyone needing help after the marathon explosions:
Runner Darren Foy, 40, from Southampton and his wife Sandra and their two children missed the explosions by just 30 minutes after he finished the marathon in three and half hours.
Speaking from the city, the chartered surveyor said: