Three people have been arrested after police discovered 28 irregular migrants hidden inside ‘safe houses’ in Ceuta.

The two properties were located in El Principe and Loma Colmenar following an investigation by the Policia Nacional.

Among those found inside were three minors, who have since been placed into care.

Police said the properties were being used to conceal migrants during their stay in the Spanish enclave in exchange for money or unpaid construction work.

The most disturbing conditions were uncovered inside an unfinished two-storey building in El Principe.

Numerous people were found sleeping on mattresses spread across the floor of the overcrowded property.

The building had no running water, electricity, proper ventilation or kitchen facilities and failed to meet even the most basic standards for human habitation, according to investigators.

The second property in Loma Colmenar was similarly small and allegedly used to keep migrants hidden from the authorities.

Police believe different people managed the two locations, arranging access and allowing migrants to remain there in return for payments.

The amount charged varied according to each migrant’s financial circumstances and the size of the space they occupied.

In some cases, migrants are suspected of having paid for their accommodation by carrying out renovation, construction or extension work on the properties.

Investigators estimate the scheme had generated more than €10,000 between the migrants’ arrival in Ceuta and the police raids.

The three children discovered during the operation were referred to organisations working with vulnerable migrants before being transferred to appropriate care facilities.