One of the protesters appeared to be hit by one of the security member's baton, while another was carried out of the venue by his arms and legs.
For his part, Sanders did not seem rattled.
"We don't get intimidated easily," he said, after the protesters had been removed.
Sanders’ campaign spokesperson, Michael Briggs, said he thought security handled the episode “professionally,” although a media spokesperson for the group organizing the protest said one of its members was “assaulted.”
Zach Groff of the grassroots group Direct Action Everywhere told ABC News that they have been targeting Sanders because of his message about caring for the most vulnerable.
“His campaign has promoted itself based on this idea of progressivism and rejecting discrimination and inequality," Groff said, "but when it comes to the animals in the United States and around the world, discrimination and violence is the name of the game every single day.”
“He claims to be a progressive, but you cannot be a progressive if you oppose animal rights," he said.
In a statement, another one of the Berkely-based group's organizers, Aidan Cook, said that “Sanders claims to oppose ‘factory farming,’ but what he hides is that virtually all farms in the United States, including farms he supports, are essentially factory farms."
"What we’ve learned in the case of human oppression applies to animals too: when we see someone as an object, all sorts of horrors, notably factory farming, are not just possible but inevitable,” Cook said.
The group is seeking an endorsement of full “personhood” for all animals and has previously disrupted Sanders' events.