Police in Britain say they are reviewing security plans for Sunday's marathon in London, after bomb explosions at the Boston Marathon killed at least two people.
Marathon organizers in London say they have contacted police to discuss the security plans as soon as they heard about the explosions in Boston.
Thousands of athletes are scheduled to compete in the London Marathon, less than a week away.
The London Marathon's chief executive, Nick Bitel, said the race's security procedures will be examined before any decision is made about the upcoming race. He also expressed sadness and shock about the news from Boston, saying it is a sad day for athletics.