During the early hours of yesterday morning, someone broke into a farm in Bando, near Santiago de Compostela, and let around 20,000 minks out of their cages.
This is the second time that the farm has been targeted, the first being in July 2005, when a radical group of ecologists, calling themselves the 'Animal Liberation Front', claimed responsibility, although it is not known if the same group was responsible this time around.
Regional Environment department staff have been trying to round up the minks since first light yesterday, though it is not known exactly how many animals escaped.
The public has been warned not to approach the animals, which, apart from representing a threat to the local ecosystem, have "very strong teeth" and can be "very aggressive."
The animals are not autochthonous to Galicia and their chances of survival are very low.
However, they need to feed regularly and it is feared that they may prey on small local species.
A spokesman for the regional Environment ministry has described the incident as an act of "criminal vandalism."