Russian forces and equipment went on to participate in the Second Battle of Donetsk Airport and the Battle of Debaltseve. A report released by the Royal United Services Institute in March 2015 said that "the presence of large numbers of Russian troops on Ukrainian sovereign territory" had become a "permanent feature" of the war in Donbas since the August 2014 invasion. Following the Ukrainian defeat at Debaltseve, the parties to the conflict signed the Minsk II agreement to end the fighting on 15 February 2015. These terms were highly favourable to Russia, in that they required Ukraine to grant "special status" to the separatist-held areas, and reintegrate them into Ukraine, similar to the federalisation espoused by pro-Russian protesters in early 2014. This would establish a Russian "strategic hook" within Ukraine that could be used to prevent future integration of that country with the European Union or NATO. In a press conference on 17 December 2015, Russian president Vladimir Putin acknowledged for the first time that there had been a Russian military presence in the Donbas region, though he said that this did not mean that there were "Russian troops" there. On 24 April 2019, President Putin issued an executive order fast-tracking the process for obtaining Russian citizenship for residents of the territories held by the DPR and the LPR. This is similar to what Russia has done in other pro-Russian protectorates established following post-Soviet conflicts, including in Transnistria, Abkhazia, and South Ossetia.