Spain announced Thursday it will build shelters for 1,800 migrants in its North African enclave Ceuta to ease a humanitarian crisis following last month’s influx from Morocco.

Some 72,000 migrants breached the border in an unprecedented and deadly rush into the north African territory on July 30-31, with 70,000 having since returned to Morocco, according to Spanish government figures.

But the thousands who remain, including unaccompanied children who cannot be summarily deported, are struggling to access food, water, shelter and sanitation while the tiny city's resources are overwhelmed.

Many have spent the past three weeks sleeping on the streets or on the beach, with non-governmental organizations (NGO) warning that women and girls are particularly vulnerable.

Locals have complained about insecurity and hygiene problems linked to the homeless migrants roaming the streets, accusing the government of neglecting Ceuta.

The migration ministry said the two new shelters were "temporary reception facilities that will be expanded progressively as the adaptation work on the other planned spaces is completed."

The priority of the "voluntary" transfer was to offer "an alternative accommodation and reception space so that they (the migrants) no longer have to spend the night on the streets or on the beach," the ministry said.

The migrants' future has sparked a political battle between Spain's left-wing central government and regions governed by the main conservative Popular Party (PP) and far-right Vox, which resist taking in unaccompanied children under existing legal provisions.

The government aims to transfer 500 girls to mainland Spain, but the PP has demanded the expulsion of all the remaining migrants.

"In Spain, mass deportations of minors are illegal," Secretary of State for Children Ruben Perez Correa responded during an interview with Cadena SER radio Thursday.

The unaccompanied girls in Ceuta, some as young as 10 or 11 years old, come from "very complex family situations" and "require specialized care," he said.

Earlier Wednesday, Spain's Migration Minister Elma Saiz revealed that the government plans to transfer around 500 particularly vulnerable unaccompanied minors to the mainland.

In an interview with public broadcaster RNE, Saiz said the central government in Madrid was working together with Ceuta authorities and Spain's regional governments on a plan to relocate the children, who would be placed under the care of child protection organizations on the mainland.

Spanish media reported that the plan envisages "the binding and solidarity-based reception of minors by all regions" of Spain, as well as placements with foster families. The figure of around 500 minors is provisional and may change.