accordance with the UN Charter. In particular, “States shall co-operate with other States in the maintenance of international peace of security … and] shall co-operate in the promotion of universal respect for, and observance of, human rights and fundamental freedoms for all … . 153 If depriving a person of their nationality for national security reasons increases security risks for the host State or the international community, such depreciation may be contrary to principle of international co-operation as reiterated by Principle 11. 84. At the European regional level, the 2005 Council of Europe (CoE) Convention on the Prevention of Terrorism and its Additional Protocol also include the obligation for States Parties to prevent terrorist offences and, “if not prevented, to prosecute and ensure that they are punishable by penalties which take into account their grave nature .154 In particular, the Convention demonstrates in Article 14(1)(c) “when the offence is committed by a national of that Party and 14(3) that a State has a responsibility in this regard when it concerns a national of that State or someone who is present in its territory.155 States Parties should therefore prosecute the alleged terrorist instead of depriving a person of nationality and deporting this person or preventing him from re-entering the country. States are under the obligation to prosecute persons suspected of terrorist acts if they have jurisdiction and “the deprivation of nationality on grounds related to terrorism may not serve as a pretext for doing away with the State’s responsibility to prosecute a terrorist .156 On international cooperation please also refer to Principle 11. 85. Regardless of the stated purpose, the punitive impact of deprivation of nationality renders the measure untenable under international law. Deprivation of nationality renders an individual an alien with regard to their former State of nationality, meaning that they no longer hold the rights they held as nationals. This can cause cumulative human rights violations, with particularly severe consequences if deprivation results in statelessness: 157 “Arbitrary deprivation of nationality leads the affected persons to become noncitizens with respect to the State that deprived them of their nationality. Arbitrary deprivation of nationality, therefore, effectively places the affected persons in a more disadvantaged situation concerning the enjoyment of their human rights because some of these rights may be subjected to lawful limitations that otherwise would not apply, but also because these persons are placed in a situation of increased vulnerability to human rights violations.”158 Consequential human rights violations therefore indicate that the measure of deprivation of nationality is unreasonably punitive and may be untenable under international law. Whether this 153 Declaration on Principles of International Law concerning Friendly Relations and Co-operation among States in accordance with the Charter of the United Nations, UNGA Res 26/25 (XXV) (adopted 24 October 1970) UN Doc A/RES/2625(XXV), p. 123. 154 Preamble to the CoE Convention on the Prevention of Terrorism (adopted 16 May 2005, entered into force 01 June 2007) CETS No. 196. 155 Article 14 Convention on the Prevention of Terrorism: “1. Each Party shall take such measures as may be necessary to establish its jurisdiction over the offences set forth in this Convention: […] c. when the offence is committed by a national of that Party. […] . Each Party shall take such measures as may be necessary to establish its jurisdiction over the offences set forth in this Convention in the case where the alleged offender is present in its territory and it does not extradite him or her to a Party whose jurisdiction is based on a rule of jurisdiction existing equally in the law of the requested Party.” 156 CoE Bureau of the European Committee on Legal Co-Operation (CDCJ-BU , ‘Nationality issues and the denial of residence in the context of the fight against terrorism. Feasibility study’, CDCJ-BU (2006) 22, available at: https://rm.coe.int/168070029a, para 4.4. 157 UN Human Rights Council, ‘Human rights and arbitrary deprivation of nationality: Report of the Secretary General’, A HRC 8 (2013), para 23. 158 UN Human Rights Council, ‘Human rights and arbitrary deprivation of nationality: Report of the Secretary-General’, A HRC , available at: https://undocs.org/en/A/HRC/19/43, para 47. 51