The UCI Track Champions League's final stop of the season in London was cancelled Saturday following a frightening crash involving British rider Katy Marchant and German Alessa-Catriona Propster.

The accident occurred during the women's keirin race as Propster was positioned inside of Marchant. 

The German suddenly rode high, taking herself and Marchant toward the barrier. The two riders then sailed over the barrier and into the crowd.

Marchant, an Olympic and world champion, received treatment for a broken forearm and was taken to hospital. 

Spectators were also injured, but no one was seriously hurt.

"We can confirm that two riders and four spectators received medical treatment following an incident during tonight's UCI Track Champions League event at Lee Valley VeloPark, in London," The Union Cycliste Internationale said in a statement. 

"The event medics responded immediately, with one rider transferred to the hospital. WBD Sports, British Cycling, Lee Valley VeloPark, and the Union Cycliste Internationale unanimously decided to suspend all further racing for the evening and want to extend their best wishes for a speedy recovery to both riders and all affected spectators. We also wish to thank the medical staff for their prompt response and ongoing support."

WATCH | Scary crash cancels track cycling event: 

Horrific crash cancels final round of UCI Track Cycling Champions League

During final round action of the UCI Track Cycling Champions League in London, England, a terrible crash involving Katy Marchant of Great Britain and Germany's Alessa-Catriona Propster cancelled the remainder of the event. Marchant suffered a broken forearm but there were no serious injuries.

Marchant won the team sprint gold alongside Sophie Capewell and Emma Finucane at the Paris Olympics, and the same trio won gold again in the same event at the world championships in Denmark in October.

Prior to the women's keirin race, Victoria's Sarah Van Dam failed to hold on to her second-place spot after finishing fourth.

The status of Canada's Dylan Bibic remains up in the air. 

The Mississauga, Ont, native was leading the men's endurance category by 20 points, but the elimination race was among the disciplines cancelled.