Grande-Marlaska said migrants who entered irregularly would not be allowed to stay in the territory, travel to mainland Spain or ‌obtain legal status, except in rare cases involving extreme vulnerability. Those without a right to remain would be returned to Morocco, he added.

Earlier this week, Rabat said it was monitoring “the circulation of social media posts and messages of unknown origin” calling for a mass crossing on 15 August, warning it would prosecute organisers and participants.

A Reuters witness saw reinforced security near the border, including police vans with wire shields and road checkpoints. Local media reported similar measures near Melilla, another Spanish territory in north Africa.