London Marathon Chief Executive Nick Bitel has confirmed that the security measures for Sunday's event will be reviewed following today's explosions during the Boston Marathon.

At least two people have died and dozens more have been injured following the explosions, both of which happened towards the finish line of the Boston event this afternoon.

Bitel passed on his condolences to all those affected by the Boston blast as well as revealing that he has been in contact with the Metropolitan Police regarding Sunday's race.

"We are deeply saddened and shocked by the news from Boston. Our immediate thoughts are with the people there and their families. It is a very sad day for athletics and for our friends and colleagues in marathon running," said Bitel.

"Our security plan is developed jointly with the Metropolitan Police and we were in contact with them as soon as we heard the news."

Met Police Chief Superintendent Julia Pendry added that they will be looking at the existing security arrangements before the Marathon takes place.

"A security plan is in place for the London Marathon. We will be reviewing our security arrangements in partnership with London Marathon," she said.

The London Marathon is regarded as one of the biggest sporting events on the long-distance calender.