MELBOURNE, Australia (AP) — A woman has sustained severe injuries to an arm when she was attacked by a lion at an Australian zoo.

The Darling Downs Zoo in Queensland state said the 50-year-old woman was watching animal keepers working in the zoo’s carnivore precinct before opening hours Sunday morning when she was attacked.

She was flown by helicopter from the rural town of Pilton to the state capital Brisbane where she underwent surgery. Her condition was stable, the zoo said in a statement Sunday. Several news media reported the woman lost the injured arm.

The zoo said staff were working with government workplace safety investigators to determine how the incident happened. The state government confirmed an investigation was underway.

“Inexplicably, at this stage, one animal grabbed her by one arm and caused severe damage to it,” the zoo statement said.

“At no stage did this animal leave its enclosure and there was no risk at all to staff members or members of the public.”

The woman was not a staff member but a “much loved member” of the zoo’s “family,” the statement added.

She had watched keepers at work many times over the past 20 years and was “well versed in safety protocols around potentially dangerous animals,” the zoo said.

Staff at the 48-hectare (119-acre) zoo declined media interviews on Monday. The zoo planned to reopen Tuesday for the first time since the attack.

“The animal will definitely not be put down or punished in any way,” the statement said.

Five years ago, two lions mauled and critically injured a keeper inside their enclosure at the Shoalhaven Zoo in the state of New South Wales.