Determined to show solidarity with Boston, the London Marathon will go forward as planned Sunday with a race that will be watched by about 1 million spectators and take runners past some of the city's most revered landmarks.

The British capital has long been a target for terrorists, and concerns have only intensified after Monday's harrowing scenes at the Boston Marathon. Two bombs killed three people and injured more than 170.

After high-level talks with police and authorities, organizers on Tuesday confirmed that the London Marathon will proceed while acknowledging that a race of more than 26 miles that traverses a city cannot be entirely without risk.