An investigation is under way after a trainee at Belfast Zoo was locked in with lions at the enclosure earlier this month.

Belfast City Council said it takes "the safety of all our staff, visitors and animals very seriously" and the circumstances are being investigated.

BBC News NI has been told the person involved was over the age of 18 and was at the zoo "in a training capacity".

The British and Irish Association of Zoos and Aquariums has been informed and said it will be working with the zoo throughout the investigation process.

Belfast Zoo is home to a pride of Barbary lions., with one male lion named Qays and two females, Fidda and Theibba.

Its website said the breed is "one of the largest lion sub-species".

"This big cat measure one metre in height at the shoulder and up to three and a half metres in length.

"Average weight can be up to 230 kilograms."

In a statement, Belfast City Council said it is aware of an incident at the lion enclosure at Belfast Zoo earlier this month.

"We take the safety of all our staff, visitors and animals very seriously, and an investigation is under way into the circumstances of this incident," it added.

"We cannot comment further while this is ongoing."

The incident was also reported to the Health and Safety Executive.