By Jane Kim

FARGO, N.D. (KVRR/CNN) - Sheep used for research and teaching at North Dakota State University were attacked and killed by dogs.

This is the first time the university has had to deal with such a tragedy.

One dozen sheep are dead after two dogs entered the NDSU research barn and attacked the animals.

"People who work out here discovered a couple of husky dogs had gotten into the sheep barns and attacked several sheep and there were some, some sheep were dead already and some were in various stages of dying," said Lt. Greg Stone with NDSU campus police.

According to police, the dogs entered the barn by jumping over the fence that contain the sheep.

Officials say that seven sheep were killed and five were humanely euthanized. Twelve are dead all together.

The two dogs had tags listing a North Fargo address. They have been impounded and are not expected to be euthanized.

NDSU department head of Animal Sciences Greg Lardy says it is a personal loss.

"It's disheartening to see this happen and like I said before our employees are student workers, they're the people that are directly affected by this, they're hurt, they were upset and I fully understand that," said Lardy.

Hopefully, this is the only and last encounter these sheep will have with neighboring predators.