76 stage of the evolution of international law, to jus cogens.287 Consequently, States may not discriminate or tolerate discriminatory situations that prejudice migrants. However, the State may grant distinct treatment to documented migrants with respect to undocumented migrants, or between migrants and nationals, provided that this differential treatment is reasonable, objective, and proportionate and does not infringe upon human rights.288 Consequently, States are obliged not to introduce discriminatory regulations into their laws, to eliminate regulations of a discriminatory nature, to combat practices of this nature, and to establish norms and other measures that recognize and ensure the effective equality before the law of each individual.289 249. In such respect, this Court has established that it cannot ignore the particular seriousness of the finding that a State Party to the Convention has carried out or has tolerated a generalized practice of human rights violations in its territory. This requires the Court “to apply a standard of proof which considers the seriousness of the charge and which, notwithstanding what has already been said, is capable of establishing the truth of the allegations in a convincing manner.”290 The Court has established that “the confirmation of a single case of violation of human rights by the authorities of a State is not in itself sufficient ground to presume or infer the existence in that State of widespread, large-scale practices, to the detriment of the rights of other citizens.”291 250. The alleged context of generalized discrimination constitutes, then, an issue of fact. Therefore, the alleging party must offer evidence to sustain the argument. In this respect, the Court notes that the representatives do not make reference to specific evidence or evidence specifically furnished in the case-file of this case to base such affirmation. After the request of evidence to facilitate adjudication of the case in this respect (supra para. 79), the representatives made reference to reports of United Nations Rapporteurs or other reports of non governmental organizations or private individuals. 251. Considering the documents furnished by the representatives, the Court does not find grounds to consider said context proven, due to the fact that some of said references are not related to the particular situation in Panama; some of the documents were prepared after the time of the events of this case, and those documents that make reference to alleged discriminatory practices refer specifically to refugees and migrants coming from Colombia. In sum, there are not sufficient facts in the case file for this Tribunal to decide that this case was framed within the alleged situation. Moreover, the phenomenon of criminalization of irregular immigration has already been analyzed in light of the obligations contained in Articles 7 and 2 of the American Convention (supra paras. 161 to 172). 252. The representatives, moreover, considered that the human rights violations committed against Mr. Vélez Loor must be necessarily assessed in light of the obligations established in Articles 24 and 1(1), both of the Convention, by virtue of 287 Cf. Juridical Condition and Rights of the Undocumented Migrants, supra note 82, para. 101; Case of The Xákmok Kásek Indigenous Community, supra note 28, para. 269, and Case of Servellón García et al., supra note 48, para. 94. 288 Cf. Juridical Condition and Rights of the Undocumented Migrants, supra note 82, para. 119 289 Cf. Proposed Amendments of the Naturalization Provisions of the Constitution of Costa Rica. Advisory Opinion OC-4/84 of January 19, 1984. Series A No. 4, para. 54; Case of the Yean and Bosico girls v. República Dominicana. Preliminary Objections, Merits, Reparations, and Costs. Judgment of September 8, 2005. Series C No. 130, para. 141, and Case of Yatama, supra note 38, para. 185. 290 Case of Velásquez Rodríguez, supra note 51, para. 129; Case of Perozo, supra note 9, para. 148, and Case of Ríos et al. v. Venezuela. Preliminary Objections, Merits, Reparations, and Costs. Judgment of January 28, 2009. Series C No. 194, para. 136. 291 Case of Gangaram Panday, supra note 172, para. 64.