Spanish officials said at least 67 people died while attempting to reach Ceuta, Spain’s autonomous city on the North African coast, from Morocco.
Spain’s government had earlier confirmed 57 deaths, while Ceuta regional chief Juan Jesús Vivas had initially put the number at 34.
Spain’s Interior Ministry said about 50,000 people crossed the border from Thursday morning, while Vivas estimated that as many as 60,000 may have crossed over several days.
Officials said some people drowned at sea and others died in crushing or trampling near breakwaters and border fences.
Spanish officials said further casualties may have occurred on the Moroccan side of the border, leaving the overall toll uncertain.
The Interior Ministry said 48,300 people had returned to Morocco by 6 p.m. on Friday.
Foreign Minister José Manuel Albares said nearly everyone who entered Ceuta had returned to Morocco.
Prime Minister Pedro Sánchez visited Ceuta on Friday and described the mass crossing as a violation of Spain’s territorial sovereignty.
Sánchez alleged that smuggling networks had encouraged people to travel by circulating a self-interested interpretation of a recent Supreme Court ruling.
Spain announced plans for a new containment barrier along the sea-facing section of the border.
European Commission President Ursula von der Leyen called for action against smuggling networks and for the return of people entering the European Union irregularly.