Spanish authorities were facing criticism, after a video showing security forces in the northwest African enclave city of Melilla beating an illegal migrant unconscious before handing him back to Moroccan authorities was posted online.
The incident happened earlier this week, as some 300 African asylum seekers attempted to cross into the Spanish territory, scaling the six-metre (20-foot) high, triple-layer fence separating it from Morocco.
Camera footage released by rights group Prodein shows Civil Guard officers as they try to force down a group of migrants perched on the fence.
As one of them nears a ladder provided by police and attempts to descend, he is repeatedly hit by policemen with batons. After a blow to the head, the man crashes to the ground unconscious.
Officers drag him to a nearby road and leave him lying there for a couple of minutes. A medical car and an ambulance drive past without stopping.
Still unconscious, the man, identified by Prodein only as Danny, a 23-year-old from Cameroon, is then hand-carried back to the Moroccan side of the fence, without receiving any medical attention.