A three-year-old polar bear has died at the Assiniboine Park Zoo in Winnipeg.

The zoo issued a statement on Sunday that said Eli passed away Saturday afternoon.

“Eli began exhibiting mild clinical symptoms on Friday and received treatment from veterinary staff at that time,” the zoo said.

“By Saturday his conditioned had worsened significantly and the decision was made to anesthetize him in order to determine the cause of illness,” the statement goes on.

“Despite best efforts by veterinary and animal care professionals Eli passed away shortly after being anesthetized.”

Preliminary results from a necropsy suggest that internal swelling of tissues in the throat and neck may have interfered with Eli’s breathing and caused his the death.

“With this diagnosis, there is no concern for the other polar bears or animal species at the Zoo,” according to the zoo’s statement.

“We are all deeply saddened by Eli’s passing,” the zoo added. “He was a part of our zoo family and this is a heartbreaking loss for our staff, volunteers, and visitors."

Corinna Wolke, who was visiting the zoo Sunday, said she was shocked to hear of Eli's death.

"It’s very saddening, because every year I bring my kids here to see the polar bears," Wolke said. "The polar bears are the main attraction."

Eli arrived at the Winnipeg zoo in 2015, along with his brother, from Churchill, Man. Their mother had been shot and it was feared that the cubs would not survive on their own.

With a report from CTV Winnipeg