Putin cited "the accession of the Republic of Crimea and Sevastopol into Russia" and resulting "practical end of renting relationships" as his reason for the denunciation. On the same day, he signed a decree formally rehabilitating the Crimean Tatars, who were ousted from their lands in 1944, and the Armenian, German, Greek, and Bulgarian minority communities in the region that Stalin also ordered removed in the 1940s. Also on 31 March 2014, the Russian Prime Minister Dmitry Medvedev announced a series of programmes aimed at swiftly incorporating the territory of Crimea into Russia's economy and infrastructure. Medvedev announced the creation of a new ministry for Crimean affairs, and ordered Russia's top ministers who joined him there to make coming up with a development plan their top priority. On 3 April 2014, the Republic of Crimea and the city of Sevastopol became parts of Russia's Southern Military District. On 7 May 2015, Crimea switched its phone code system from the Ukrainian number system to the Russian number system. On 11 April, the Constitution of the Republic of Crimea and City Charter of Sevastopol were adopted by their respective legislatures, coming into effect the following day in addition the new federal subjects were enumerated in a newly published revision of the Russian Constitution. On 14 April, Vladimir Putin announced that he would open a ruble-only account with Bank Rossiya and would make it the primary bank in the newly annexed Crimea as well as giving the right to service payments on Russia's $36 billion wholesale electricity market – which gave the bank $112 million annually from commission charges alone. Russia withdrew its forces from southern Kherson in December 2014. In July 2015, Russian Prime Minister, Dmitry Medvedev, declared that Crimea had been fully integrated into Russia. Until 2016 these new subjects were grouped in the Crimean Federal District. On 8 August 2016, Ukraine reported that Russia had increased its military presence along the demarcation line. In response to this military buildup Ukraine also deployed more troops and resources closer to the border with Crimea. The Pentagon has downplayed a Russian invasion of Ukraine, calling Russian troops along the border a regular military exercise. On 10 August, Russia claimed two servicemen were killed in clashes with Ukrainian commandos, and that Ukrainian servicemen had been captured with a total of 40 kg of explosives in their possession. Ukraine denied that the incident took place.