Anti-migrant fury spilt onto the streets of Spain's North African enclave of Ceuta on Thursday, with protesters storming beach camps, trashing migrants' shelters and belongings and throwing some onto fires.

Protesters marched through Ceuta carrying Spanish flags and chanting 'out', 'expulsion' and 'invaders', before blocking roads.

Demonstrators stopped Red Cross vehicles trying to deliver food to hundreds of migrants staying around Trampolin Beach. The vehicles were initially unable to get through before police intervened.

The scenes followed another tense night in Ceuta, with reports that security forces fired warning shots into the air as residents tried to reach migrants on the beaches.

Authorities say 12 Moroccan migrants were arrested after a separate incident involving a military vehicle carrying four Spanish soldiers early on Thursday.

The unrest follows the extraordinary mass crossing from Morocco on July 30, when around 72,000 people entered Ceuta irregularly in less than 48 hours, plunging the Spanish territory into a major humanitarian and political crisis.