At least 18 African migrants died while trying to swim from Morocco’s Castillejos to Spain’s Ceuta.
Most of those who died were young men who tried to cross the maritime border by overcoming breakwaters and barriers.
As many as 1,500 people crossed from Morocco to Ceuta over the past week, most of them by swimming. Official authorities have not yet confirmed the figure.
Meanwhile, security forces had previously detained more than 800 irregular migrants who tried to swim along the same route.
Spanish Prime Minister Pedro Sánchez said the government would mobilize all its resources in response to the incident.
The Spanish government decided to deploy troops to the area after irregular migration attempts toward Ceuta increased.