LONDON (AP) — Princes William and Harry have come out to Greenwich Park to cheer on their cousin Zara Phillips, Queen Elizabeth II's granddaughter. She's due to compete in the difficult and dangerous cross-country portion of Olympic equestrian eventing.

William's wife, Kate, and Prince Charles' wife, Camilla, are also in the stands of the main arena ahead of Phillips' ride. Seated with them are their cousins Princess Beatrice and Princess Eugenie.

A half-dozen riders have fallen off their mounts in the twisting, hilly 28-obstacle course midway through the competition. Australia's Christopher Burton, riding HP Leilani, led the pack Monday after a clean round under the time limit.

Eventing includes dressage, cross-country and jumping.