Although detention of asylum seekers or vulnerable categories is not explicitly allowed by law, in practice several exceptions have been reported concerning unaccompanied children and victims of trafficking. This is due to the lack of identification of the minor age of the person, or of his or her status of victim of trafficking. For example, according to the annual report issued by the Ombudsman in its capacity of National Prevention of Torture Mechanism, 44 persons were identified as minors at CIEs in 2020, the highest number being detained in the CIEs of Madrid and Barcelona. In its 2021 report on CIEs, the Jesuit Refugee Service highlighted the persistent problem of a lack of identification of unaccompanied children when already detained at CIEs. Moreover, the organisation observed that both the police and public prosecutors showed resistances in accepting identification documents (e.g. birth certificates, passports, etc.) indicating a different age from that reported in the passport of the interested person. Because of this, they usually proceeded in carrying out an age assessment in order to obtain a bigger margin to declare the majority of age the applicant.
According to the annual report of the Public Prosecutor Office, a total of 10 people alleged to be minors while in detention at CIES in 2020. Out of them, just one was finally recognised as a minor.
Nonetheless, when they are identified as minors or victims while they are in detention, they are released and handled to the competent protection systems. In addition, applicants such as pregnant women or persons requiring assistance may be exempted from the border procedure and admitted to the territory in specific cases.
 Article 62(4) Aliens Act.
 Article 62-bis(1)(i) Aliens Act. The part of this provision, referring to the need for CIE to guarantee family unity, has been set aside by the Supreme Court: Tribunal Supremo, Application 373/2014, 10 February 2015.