A woman in her 50s is believed to have lost an arm when a lion mauled her at an Australian zoo Sunday morning, according to authorities and reports.

The frightening event took place around 8:20 a.m. at Darling Downs Zoo near Toowoomba, Queensland, as the woman — a frequent visitor — observed zookeepers tending to the animal, according to the zoo’s statement.

“This morning, a much-loved member of our family was watching keepers working in the carnivore precinct,” the zoo said in a statement.

The woman had “done this many many times over the past 20 years,” the statement read.

“She is knowledgeable about safety measures concerning potentially dangerous animals. … For reasons unknown at this point, one of the creatures grabbed her arm and inflicted severe harm,” the zoo reported.

It remains unclear exactly where the woman was positioned during the attack. She was flown to Princess Alexandra Hospital in Brisbane with a “significant arm injury” and was in stable condition while receiving surgical treatment.

The animal that mauled the woman was a lion, and the lady is believed to have lost her arm in the attack, the Daily Mail reported.

The lion never left its enclosure during the incident, the zoo stressed.

The animal will not be euthanized, the Daily Mail reported.