Newmarket, located about 60 miles from London, maintained its schedule for a seven-race program that included the $469,975 Darley July Cup (Eng-G1). Thursday marks the final day of the annual three-day meet.

Citing police requests that people in the London area limit themselves to only essential travel, officials at Epsom decided to call off their day's racing.

Explosions on the London subway system and a double-decker bus killed at least 37 people and injured about 700, the Associated Press reports. Epsom is located less than 20 miles from the center of London.

Epsom initially planned to contuct racing, advising racegoers that travel to and from the track would not "be easy." But the track later said that with the transport system effectively closed and considering its status as a London racecourse it would be "inappropriate" to race.

Folkestone racecourse in Kent, England, conducted live racing as scheduled on Thursday.--Colin Cameron