Five lions escaped their enclosure at Sydney's Taronga Zoo, forcing staff to take refuge and placing the zoo into lockdown.
Taronga issued a statement confirming the incident early on Wednesday, saying all the lions were back in their enclosure.
"An emergency situation occurred this morning at Taronga Zoo Sydney when five lions were located outside their enclosure," it said.
Aerial footage showed keepers patrolling the ground during the emergency.
"The zoo has strict safety protocols in place for such an incident.
"All persons on site were moved to safe zones and there are no injuries to guests or staff.
"All animals are now in their exhibit where they are being closely monitored."
The zoo, at Mosman on the city's north shore, will be open as normal on Wednesday.
Independent local newspaper the Mosman Collective reported that a "code one" was issued shortly after 7.30am on Wednesday.
"Staff were told to go to a safe haven," the paper's Facebook page says.