Police in Surrey, England, arrested 19 people on Saturday "in connection with planned criminal disruption" before the Epsom Derby Festival, one of the oldest and most famous horse races in the world.
The Jockey Club, which runs the Epsom racecourse, won a High Court injunction last month to stop animal rights protesters from disrupting the event.
Animal Rising, an animal rights group, had planned to demonstrate at the Derby, calling on "as many animal lovers as possible to peacefully descend on Epsom" in a post on Twitter.
The Jockey Club said it had offered Animal Rising an area near the entrance to protest. Photos from the event on Saturday showed a small group of activists had gathered outside the main gates holding signs that read: "Animal abuse is not sport" and "For All Life."
Surrey Police said in a statement that 11 people were arrested in the early hours of the morning "following warrants based on intelligence received," while another eight were arrested after their vehicle was stopped.
CNN has reached out to Animal Rising for comment and to confirm whether those arrested were members or supporters of the group.
Animal Rising called the arrests "police overreach" in a statement on Saturday, claiming that they were "another example of how the Government is attempting to outlaw all protests and ignore critical societal issues," using new policing powers granted under the Public Order Bill.
Parts of the bill, which empowers British police to take stronger action against peaceful protesters, came into force last month despite criticism from human rights groups. The Home Office said the measures will "give police the powers to prevent disruption at major sporting and cultural events taking place this summer in England and Wales."
CNN reached out to the Home Office for comment on the arrests, and Animal Rising's statement.
Two months ago, in April, more than 100 people were arrested at the Grand National in Aintree, Liverpool, regarded as a national institution by many in the United Kingdom -- but it is also one of the most controversial horse races in the world.
The race, which has been modified in recent years to ease safety concerns, sees a field of up to 40 horses jumping 30 fences roughly the size of small cars. The demanding course has resulted in multiple fatalities over the years. According to animal rights organization PETA UK, 36 horses have died at the festival since 2010.
Animal Aid, which was also involved in the protests at the Grand National, has called for jump racing to be banned. The British Horseracing Authority (BHA) condemned the protests at the time, saying they were "reckless and potentially harmful."
Meanwhile, in the United States, horse safety has also been in the spotlight. After the death of 12 horses in May, the owner of Churchill Downs, the racetrack that hosts the Kentucky Derby, announced it would suspend all racing operations to conduct a "top-to-bottom" review of all safety and surface protocols.