BRANT COUNTY, Ont. -- Police are investigating after an alleged act of vandalism let loose about 500 minks in southwestern Ontario.

Ontario Provincial Police say they were called to a farm in Brant County after a report of a break in Saturday morning.

Investigators say holes were cut into the walls of the farm, and mink were let out of their cages.

Police say the animals had recently given birth and their newborns -- called kits -- were separated from their mothers.

Police say most of them were recovered, but many of the kits may not survive the trauma of separation.

Nancy Daigneault, a representative from the International Fur Federation, says it has "all the markings" of an act by "animal rights extremists".

She says mink farms are targeted fairly regularly by activists, and some groups will take credit for the acts online.

But Const. Ken Johnston says that so far, there's no concrete evidence pointing to activists. He says police are continuing their investigation, and they're asking for anyone with information to come forward.