A vigil is being held by an animal activist group after a truck carrying pigs rolled over, killing about 40 of them while they were en route to a slaughterhouse on Wednesday.

Those who want to join can bring candles, flowers or message for the lost lives to Fearmans Pork Plant, according to Toronto Pig Save. They said the vigil will be held until Thursday at noon.

The pigs were killed in a crash that happened just after 7 a.m. near Harvester Road and Appleby Line.

Halton Regional Police said a truck carrying approximately 180 pigs somehow lost control and flipped over, causing the roof of the vehicle to break open.

The 25-year-old driver, of Brunner, Ont., was transported to hospital and treated for minor injuries.

Initially, it was unclear whether the pigs were injured in the crash but images from the scene show some of the animals with blood on them. Police later confirmed that approximately 40 of the pigs – headed to Fearmans Pork Plant -- died as a result of the crash.

Shortly after the crash, several protesters flocked to the scene, prompting an increased police presence from Halton police.

An animal activist who was at the scene protesting -- and who is currently facing mischief charges for giving water to pigs that were headed to a slaughterhouse -- was arrested once again by police in Burlington.

In a video posted to Twitter, protesters can be seen holding signs reading “Go Vegan” and yelling “justice for animals.”

A spokesperson with 'Toronto Pig Save' confirmed to CP24 Wednesday afternoon that animal rights activist Anita Krajnc was detained by Halton police for “trying to help injured pigs at the crash site.” However, police did not immediately confirm the identity of the person placed under arrest at the scene.

Krajnc is currently on trial for mischief charges after giving water to another truckload of pigs back in June, 2015. Earlier this week, Krajnc, who pleaded not guilty to the charge, testified that she was “just following the golden rule” of treating the pigs as she would want to be treated.

While seated in the back of a cruiser on Wednesday, Krajnc recorded a video of herself urging supporters to call Fearmans Pork Plant.

"The pigs are being herded off to the kill farm. They should be shown mercy, not being herded to the gas chambers," she said in a video uploaded to her Facebook page. "Show them mercy. Save the pigs."

A witness also filmed the moment Krajnc was arrested as protesters shouted, "Don't let them arrest her!"

At one point, as Kranjc is led away in handcuffs, a female protester can be heard shouting, “We love you Anita.”

A spokesperson for the People for Ethical Treatment of Animals (PETA) said supporters ‘raced to the scene’ of the accident in hopes of ‘rescuing any pigs they can find.’

"The horror that puts bacon on the plate became evident today, as pigs—already scared and banged up—spilled onto the highway when a truck carrying them to their deaths in Burlington, Ontario, overturned,” PETA president Ingrid Newkirk says in the release Wednesday.

“PETA asks everyone to spare a thought and spare a pig by turning away from bacon and ham, rather than turning away from what these animals endure every day."

Halton police said representatives from Health Canada and the Ministry of Transportation attended the scene as police controlled the crowd and conducted an investigation.

They said, “measures were taken to ensure the pigs were handled as humanely as possible.”

The eastbound lane of Harvester Road from Appleby Line was closed for several hours while police investigate the circumstances surrounding the incident. It reopened at approximately 1:45 p.m.