A mass crossing that brought about 72,000 migrants into Ceuta, Spain’s North African enclave, has opened a sharp dispute between Madrid and Rabat over who bears responsibility for one of Europe’s largest sudden border movements in recent years.

Spain says about 70,000 people have since returned to Morocco, leaving roughly 2,000 in Ceuta.

The crossing, which involved people swimming around coastal barriers and breaching the land border, overwhelmed local services and caused a deadly humanitarian emergency.

Authorities have reported at least 75 deaths.

Ceuta’s facilities are also under severe pressure from the arrival of hundreds of unaccompanied children.

A Moroccan official said Spain had been warned that a 8 July Supreme Court judgment could trigger a crisis.

The ruling held that migrants intercepted at sea while trying to swim to Ceuta or Melilla cannot be subjected to summary “hot returns.” It does not prevent returns altogether, but requires the authorities to use the ordinary legal procedure, with its accompanying safeguards.

Spain rejects the suggestion that the judgment caused the influx.

Fernando Grande-Marlaska, the interior minister, said there had been no intelligence warning of an imminent mass crossing, while the government has blamed criminal networks for circulating calls encouraging people to enter Ceuta.

The origin and reach of social-media posts calling for a further crossing on 15 August have not been publicly established.

The episode has revived scrutiny of Morocco’s role as a gatekeeper for Europe’s southern border.

In 2021, during a diplomatic dispute between Madrid and Rabat, Morocco relaxed controls and about 8,000 people entered Ceuta.

Relations had been strained after Spain allowed Brahim Ghali, leader of the Polisario Front, to receive hospital treatment; Morocco regarded the move as hostile.

European interior ministers have sought to close ranks behind Spain after several days of public friction.

Italy temporarily increased checks on travel from Spain, while a group of 22 European Union countries pressed for tighter migration controls and faster returns.

The ministers agreed that the Ceuta emergency had not endangered the Schengen free-movement area, but the crisis has sharpened concern that migration can be used as leverage in disputes with neighbouring states.

The European Commission is now working with Spain on measures covering border surveillance, action against smuggling networks and co-operation with third countries.

Ceuta’s immediate challenge remains the care and legal processing of those who have not returned, especially the children for whom the enclave has far fewer places than arrivals.