Spain was seen sending in its troops to bolster security in the North African enclave of Ceuta after thousands of migrants swam from Morocco into the territory on Thursday.
At least 18 people ended up drowning while trying to get to Ceuta, local officials claimed.
They also appealed to Madrid for assistance after a recent rise in attempted crossings, but there were chaotic scenes on Thursday as border controls apparently broke down. Moreover, 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.
The country's interior ministry accused human trafficking networks of exploiting that to encourage the flow of undocumented migrants.