In June, 1917, Kolchak resigned, but was sent by Kerensky to the United States to study the US Navy, with a view to the invasion of the Bosporus. En route, he stopped in Britain where he became friendly with Admirals Hall and Jellicoe, but after his US visit, sailed to Japan, arriving shortly after the November Revolution. Kolchak then offered his services to the British Navy after the beginning of the Brest-Litovsk negotiations; his offer was accepted and he was directed to report to duty with British forces in Mesopotamia, a duty station almost immediately changed to Siberia instead. Returning to Siberia, he was appointed Minister of War and Navy in the anti-Bolshevik Socialist government established at Omsk, and then seized control to become Supreme Ruler in a coup d'etat. Kolchak proceeded to antagonise elements within the government, as well as the Czechosolovak Legion which held the Trans-Siberian Railroad, and, after a series of political and military defeats in the summer of 1919, relinquished command to General Anton Denikin on 4 January 1920. He sought Allied protection, but the Czechs instead turned him over to the Bolshevik authorities in Irkutsk where after a somewhat rigourous interrogation, he was executed by firing squad on 2 February 1920, and his body thrown into the Angara River.