Hundreds of African Sub-Saharan migrants are attempting to scale the fence between Morocco and the Spanish exclave of Melilla, defying efforts by police to prevent them entering.
The latest of these incidents saw an estimated 2,000 migrants attempted to storm the exclave on at around 5.30am local time on Wednesday.
The Spanish city's mayor Juan José Imbroda said that there were "waves of people, they were difficult to stop". Around 500 asylum-seekers managed to jump the razor wire fence.
Jorge Fernández Diaz, Spain's interior minister, said that the situation in the centers for temporary stay of immigrants (CETI), which now hosts more than 2,300 migrants, was "on the edge" after the latest arrivals.
The CETI now holds five times the number of people it was built to house. The migrants spend months there before being transferred to other countries.
In recent months, large groups have attempted to storm the 6m high (19.5ft) border fence.
On 18 March, more than 1,000 tried to scale the fence and 500 managed to jump over it. The migrants were helped by fog which left Spanish and Moroccan authorities unable to react.
As in other incidents, migrants were shouting chants of victory such as the "bosa bosa" and "Spain! Spain!"
Those who made it to the immigration centre had bruises and minor cuts, but none of the asylum seekers were seriously injured.