nature, including the 1997 Suppression of Terrorist Bombings Convention,63 the 1999 Convention on Terrorist Financing,64 and the 2005 Convention for the Suppression of Acts of Nuclear Terrorism.65 These instruments encompass contribution to specific acts, such as aircraft hijacking, hostage-taking, bombings and nuclear terrorism. Mere membership in a terrorist group or the fact of receiving training from a terrorist group generally does not constitute a terrorist act. These instruments also generally require States to prosecute or extradite individuals involved in criminal activity. States have important duties “to ensure that action is taken so that violations and abuses are prevented and/or not repeated, to promptly, thoroughly, independently and impartially investigate allegations of such violations and abuses, to punish perpetrators and to ensure an adequate remedy and redress are provided to victims.”66 This is reflected in UN Security Council Resolution 2322 of 2016, which emphasises the need for cooperation among States in order to address and counter terrorism,67 including in the context of investigation and prosecution of terrorist acts.68 Under the Resolution, “States shall afford one another the greatest measure of assistance in connection with criminal investigations or criminal proceedings relating to the financing or supporting of terrorist acts, including assistance in obtaining evidence in their possession necessary for the proceedings”.69 In addition, the 1970 Declaration on Principles of International Law Concerning Friendly Relations and Co-Operation Among States (UN General Assembly Resolution 2625) sets out the duties of States to “co-operate with other States in the maintenance of international peace and security”. In line with these duties and the general principle that States’ nationality decisions are to be given deference insofar as they are consistent with international law,70 a State should carefully consider the impact of its decision to deprive individuals of nationality on its obligations concerning the maintenance of international peace and security. Attention to a State’s own national security interests alone may not be sufficient in circumstances where it is reasonable to believe that the deprivation of nationality may negatively impact the peace and security of other States. These considerations are particularly relevant where a State seeks to undertake deprivation of nationality in 63 International Convention for the Suppression of Terrorist Bombings, 2149 UNTS 256, Article 2. International Convention for the Suppression of the Financing of Terrorism, 2178 UNTS 197, Article 2. 65 International Convention for the Suppression of Acts of Nuclear Terrorism, 2445 UNTS 89, Article 2. 66 See e.g., Human Rights Council, Report of the United Nations High Commissioner for Human Rights on the protection of human rights and fundamental freedoms while countering terrorism, 19 December 2014, A/HRC/28/28, para. 40. 67 UNSC Res. 2322, 12 December 2016, preambular para. 10: “… terrorism can only be defeated by a sustained and comprehensive approach involving the active participation and collaboration of all States … to impede, impair, isolate and incapacitate the terrorist threat”. 68 UNSC Res. 2322, 12 December 2016. UNSC Res. 2178, 24 September 2014. UN Counter-Terrorism Implementation Task Force, Guidance to States on human rights-compliant responses to the threat posed by foreign fighters, 2018, https://www.un.org/sc/ctc/wp-content/uploads/2018/08/Human-Rights-Responses-toForeign-Fighters-web-final.pdf, para. 72. 69 UNSC Res. 2322, 12 December 2016, para. 8. 70 Nottebohm Case (Liechtenstein v. Guatemala): Second Phase, [1955] ICJ Reports 4, https://www.refworld.org/cases,ICJ,3ae6b7248.html, p. 23: While “international law leaves it to each State to lay down the rules governing the grant of its own nationality”, such rules “shall be recognized by other States in so far as it is consistent with international law.”. 64 UNHCR > GUIDELINES ON STATELESSNESS NO.5 20