Nationality determination is important because Greece cannot deport nationals of certain countries and, therefore, also does not detain citizens of those countries once their national identities are established.117 Manfred Nowak, the former UN special rapporteur on torture, describes the effects of this practice in his report from an October 2010 research mission in Greece: The length of detention was witnessed to be dependent on the nationality of aliens. While aliens who cannot be deported (e.g. from Afghanistan, Somalia, Pakistan) were usually released within several days with an order to leave the country within 30 days, those that can principally be deported often had to wait up to several months in police custody. This created a feeling of extreme injustice and discrimination among the detainees.118 On January 20, 2000, Turkey and Greece signed an agreement,119 according to which thirdcountry nationals as well as nationals of Greece and Turkey who cross the Greek-Turkish border irregularly can be returned to the country from which they came. Since the two countries signed the agreement, they have consistently disagreed on its interpretation and application. As a general rule, Turkey accepts back only nationals of countries with which it has its own readmission agreements. At present, in practice, the agreement applies to Iraqi, Syrian, Iranian, and Georgian nationals.120 Irregular migrants who are not deportable under the Greece-Turkey readmission agreement may still be deported directly to their home countries. This can only happen if that country recognizes the deportee as their own national. There are particular countries, including some that do not have diplomatic missions in Greece, which do not cooperate with Greece in facilitating the deportation of their citizens. 117 Greece’s inability to return migrants from certain countries at times relates to the dangers of violence in those countries, but also sometimes relates to lack of diplomatic relations or lack of cooperation with the sending countries for accepting their nationals back. 118 Mission to Greece Report, March 4, 2011, para. 39. "Agreement between the Hellenic Republic and the Republic of Turkey on Cooperation of the Ministry of Public Order of the Hellenic Republic of Turkey on Combating Crime, especially Terrorism, Organized Crime, Illicit Drug Trafficking and Illegal Migration," January 20, 2000. For an analysis of readmission agreements and human rights, see European Parliament, Directorate-General for Internal Policies, Policy Department C: Citizens’ Rights and Constitutional Affairs, “Readmission Policy,” PE 435.632, September 2010, http://cadmus.eui.eu/bitstream/handle/1814/14957/EP_ReadmissionPolicy_en.pdf?sequence=4 (accessed April 14, 2011). 120 FRA report, p. 24. 119 41 HUMAN RIGHTS WATCH | SEPTEMBER 2011