Prime Minister Pedro Sánchez of Spain said on Monday that 5,000 migrants remained in Ceuta, weeks after more than 70,000 people surged from Morocco into the Spanish territory in North Africa.

Although most of the migrants returned home quickly, the continued presence of several thousand newcomers in a territory of just 84,000 legal residents has heaped pressure on Mr. Sánchez’ government, inflamed local tensions and served as a flashpoint in the global debate about migration.

Mr. Sánchez, speaking on the radio network Cadena Ser, said that 1,200 minors were among the remaining migrants and that his government had reached an agreement with the local authorities to build facilities to house them while officials assessed their asylum requests. The territory’s administration has a higher estimate: It says that around 9,000 migrants remain in Ceuta and it has accused the national government of failing to do enough to resolve the problem.

The territory’s migrant center is overflowing, and makeshift shelters have been built to house up to 1,500 migrants, according to the national government. Residents have called that housing insufficient because hundreds of migrants have established tents in Ceuta’s surrounding hills or on its beaches. Videos published by the Spanish news media showed that some of the migrants have staged wrestling matches to pass the time.

As Mr. Sánchez spoke, local media showed footage of Spanish police officers in riot gear watching as hundreds of migrants, almost all young men, jostled with one another on Monday morning to get a spot in one of the shelters.