Although most of about 80,000 people who swarmed into the tiny North African territory have gone back, it is estimated that 3,000 to 5,000 remain.

By the time authorities reacted, an estimated 60,000 people had reached Ceuta in just a few days, the largest migration surge between Morocco and Spain in years.

Calm is slowly returning to Spain's North African enclave of Ceuta after around 72,000 migrants crossed from Morocco in just days. Spanish officials say most have now returned,…