India, Aug. 2 -- At least 57 people have died after tens of thousands of migrants attempted to enter the Spanish enclave of Ceuta from Morocco, overwhelming border crossings by land and sea in one of Europe's largest migration surges in recent years.

Many of the deaths occurred when migrants drowned while trying to reach the enclave as security forces struggled to contain the crowds, according to authorities in Ceuta.

Spanish officials estimated that between 50,000 and 60,000 people attempted to cross into the territory, home to about 84,000 residents, since Thursday morning. By Friday evening, however, most of those who entered had returned to Morocco.

Spain said it intended to deport migrants who had entered illegally, although autho...