Spain is sending troops to bolster security in its North African enclave of Ceuta after thousands of migrants swam from Morocco into the territory on Thursday.

Axar.az reports, citing BBC, that at least 18 people drowned while trying to reach Ceuta. Local officials had appealed to Madrid for help after a recent rise in attempted crossings, but there were chaotic scenes on Thursday as border controls apparently broke down.

Spain's Supreme Court ruled this month that migrants stopped at sea while trying to reach Ceuta or Melilla, another Spanish enclave, cannot be summarily returned to Morocco.

Spain's interior ministry accused human trafficking networks of exploiting that to "encourage the flow of undocumented migrants".

It should be noted that although tens of thousands of migrants recently entered the Ceuta area illegally, the vast majority were returned following a swift response by the Spanish authorities.