Five lions escaped from their enclosure at Sydney's Taronga Zoo that caused a brief emergency on Wednesday, officials said.
According to local officials, one adult lion and four cubs were spotted outside their main exhibit.
"The lions were observed in a small area adjacent to the main exhibit, where a six-foot fence separated them from the rest of the zoo," said the Taronga Zoo in a statement.
"All persons on site were moved to safe zones. Four of the lions calmly returned to their dens, and one cub was safely tranquilized. The cub is now awake and well," it added.
According to the initial report, an integrity issue with a containment fence enabled five lions to temporarily exit their main exhibit, however, the situation was brought under control within minutes.
"This is a significant incident, and a full review is now underway to confirm exactly how the lions were able to exit their main exhibit," said the statement.