Zoo-keepers in Belfast are on the hunt for a missing lion-tailed macaque.
It was among two primates that escaped from the city zoo yesterday.
Fire crews and zoo staff, including a vet, located one of the macaques nearby but the other remains on the loose.
In a statement, Belfast Zoo said it was confident the missing macaque would be returned.
"There are continued sightings of the other macaque and staff are continuing to monitor the locations and track the movements of the animal.
"We are confident that the remaining macaque will soon be found and returned to the zoo."
Staff have urged members of the public not to approach or attempt to catch the animal but to contact the zoo immediately.
An emergency hotline has been set up so sightings can be reported.
Anyone with information is asked to contact 028 9077 6277 or 077 9627 7413 out of normal working hours.