E/CN.4/2004/76/Add.2 page 15 the country of origin or residence of his family or to keep him in Spain. The law requires the public prosecutor to order the minor’s age to be determined by means of tests in a medical centre on a priority and urgent basis whenever it cannot be conclusively established that an undocumented foreigner is a minor. The public prosecutor’s office recommends that, in the case of tests to determine the approximate age of the person concerned, it should be presumed that his age is the lowest in the age range indicated by the medical services.6 In practice, however, this recommendation is apparently not always taken into account. The Special Rapporteur interviewed two immigrants in a detention centre who appeared to be minors. 54. In the Ministry of Labour and Social Affairs she was informed that there had been no case of expulsion of unaccompanied minors. Nevertheless, during her visit to Ceuta and Melilla she received information about a number of cases of expulsion of minors; in addition, prior to that visit she had already sent an allegation about that question. 55. The Special Rapporteur believes that because of the way in which some family “reunifications” have been carried out, allegedly leaving the minor in the hands of the Moroccan police without the presence of his family or the social services, these reunifications are interpreted as expulsions. Nevertheless, many “reunited” minors return to Spain and some speak of ill-treatment by the Moroccan police. The Special Rapporteur was informed that cooperation efforts are being made with Morocco, including training of police officers and personnel dealing with minors. 56. The Special Rapporteur notes that the negotiations between Morocco and Spain focus on the question of the repatriation of migrants, especially the return of unaccompanied minors. She considers that priority should be given to ensuring that repatriations are carried out with due respect for the rights and best interests of minors. She expresses her concern at AttorneyGeneral’s instruction No. 3/2003, of 23 October 2003, which establishes that public prosecutors must press for the immediate return to their countries of origin of foreign unaccompanied minors over the age of 16 who are present in Spanish territory. 57. Nine months after having been taken into care by the public authorities and on the application of the institution providing care, the minor may be granted a residence permit, retroactive to the time when he was placed at the disposal of the juvenile protection services. There are also provisions for the granting of a work permit to minors who have reached the age of 16. The temporary residence permit expires when the boy or girl attains his or her majority. At that time he or she may apply for a permanent residence permit if they can establish that they have been in the care of a Spanish public entity for a period of at least the three preceding years or be given an extension of their temporary residence permit for humanitarian or other reasons. The relevant legislation authorizes minors who have reached the age of 14 and have been in the care of a Spanish institution to opt for Spanish nationality. 58. The Special Rapporteur visited La Purísima juvenile centre in Melilla, where she met a number of minors who had spent several years there and, on attaining their majority, had left without receiving any documentation. In some cases it may take between 20 and 25 months to obtain documentation. She was also informed that calculation of the nine-month period is interrupted if a “reunited” minor re-enters Spanish territory. 6 In order to determine age the services of forensic physicians are used, including, inter alia, bone determination techniques. The results are not 100% reliable.