More than 1,500 migrants have reached the small Spanish territory of Ceuta in North Africa within the past several days, most of them by swimming from neighbouring Morocco, authorities said on Thursday.

Many of those arriving were minors and children, Spanish public broadcaster RTVE reported.

Ceuta sits on Morocco's Mediterranean coast and is one of Spain's two territories in North Africa. It has a population of just under 85,000.

Hundreds more migrants arrived in recent hours, according to RTVE and other media citing regional authorities.

Ceuta's regional government called on Madrid to declare a national state of emergency and deploy the Spanish military to the border with Morocco.

Prime Minister Pedro Sánchez, writing on X, said his government was "mobilizing all necessary resources, working with Moroccan and international authorities, and preparing the necessary measures to restore normality as soon as possible." He gave no further details.

The Interior Ministry has ruled out declaring a state of emergency, RTVE reported. Under Spain's civil protection rules, migration movements are not among the risks covered by the national emergency system.

Spain and Morocco have agreed to strengthen cooperation in managing the arrivals and to return as quickly as possible those who entered Ceuta illegally, according to the ministry.

Opposition leader Alberto Núñez Feijóo of the conservative People's Party described the situation as "desperate" and accused Sánchez's government of failing to act.

"The government cannot look the other way on its obligations because we are facing a national security crisis," Feijóo wrote on X.

Most of the migrants reached Ceuta by swimming along the coast. Images showed mainly young men, but also families with women and children, climbing across rocks forming part of a breakwater marking the border with Morocco.

Some were seen running through the streets and shouting "Viva España!" Beaches were littered with swimming rings, flippers and wetsuits used during the crossing, RTVE reported.

Ceuta regional President Juan Jesús Vivas had said already on Wednesday that reception facilities were overwhelmed, forcing hundreds of migrants to sleep on the streets.

Not everyone attempting the crossing survives. Spain's Civil Guard recovered two bodies on Wednesday believed to be those of migrants who had tried to swim to Ceuta.

Vivas said around 60 bodies of suspected migrants had been recovered over the past 12 months.

Ceuta has long been one of the main entry points into Europe for African migrants. People regularly attempt to reach the Spanish territory by swimming along the coast or crossing the heavily fortified border with Morocco, thereby entering European Union territory.

The latest arrivals have revived memories of May 2021, when more than 8,000 people crossed into Ceuta from Morocco within 36 hours.

Madrid accused Rabat at the time of relaxing border controls to exert pressure during a dispute over Western Sahara, the former Spanish colony largely controlled by Morocco but claimed by the Polisario independence movement.

Relations improved in 2022 after Sánchez backed Morocco's autonomy plan for Western Sahara as the most serious basis for resolving the conflict. Since then, Madrid and Rabat have worked more closely on migration and security.

Some in the Spanish media have speculated that the latest surge could be linked to Sánchez's visit to Algeria last week. Morocco and Algeria are bitter rivals over Western Sahara.

There is, however, no evidence that Moroccan authorities deliberately relaxed border controls to send a political signal to Madrid.

Morocco claims both Ceuta and Melilla, Spain's other territory in North Africa, which lies about 250 kilometres further east. Thousands of migrants, many from sub-Saharan Africa, often wait near the two territories for an opportunity to enter EU territory.