Hundreds of animal activists were trying to storm a Wisconsin beagle-breeding facility and take the dogs in a "rescue" mission on April 18, fast-tracking the raid they were planning for the next day.

Dane County Sheriff Kalvin Barrett said in an update on social media that 300 to 400 people were "violently trying to break in" to the Ridglan Farms facility in Blue Mounds, Wisconsin, and were trying to "assault" deputies on the scene as of about 11:30 a.m. local time.

The action was originally planned for the morning of April 19, as the facility has been embroiled in allegations of mistreatment of animals, which it firmly denies. In March, a similar operation led to 27 people being arrested and over 20 dogs taken from the facility, which breeds the dogs to sell for scientific research.

Organizers said in a blog post the morning of April 18 that "this was the right moment, so we are seizing it."

Barrett said activists have ladders and break-in tools to get through the fence where, according to photos shared with the Milwaukee Journal Sentinel, part of the USA TODAY Network, Ridglan Farms has recently ramped up security around the facility with hay bales, moats and additional fencing.