region, and elsewhere, has been to place greater emphasis on striking at potential Black Sea and other targets utilizing stand-off air-launched cruise missiles deployed on American long-range bombers. Additionally, the United States, the United Kingdom and Turkey have entered into contracts to supply new corvettes, missile-armed fast attack craft, patrol boats and unmanned air vehicles to the Ukrainian Navy. In 2020, the Black Sea Fleet obtained seven new warships and auxiliary ships, including corvette Grayvoron, patrol ship Pavel Derzhavin, seagoing tug Sergey Balk, as well as a harbour tugs and three hydrographic survey vessels. In 2021, the same number of vessels should enter service. Russo-Ukrainian naval standoff On 29 January 2021, three US naval vessels entered the Black Sea for the first time in three years. On 1 February, the Ukrainian president Volodymyr Zelensky argued for NATO membership for Ukraine. On 19 March, another significant US naval deployment to the Black Sea took place, as cruiser USS Monterey and destroyer USS Thomas Hudner entered the sea on 19 and 20 March respectively. Prior to the scheduled deployment, on 12 March Russian cruiser Moskva made an exit to sea and on 19 March all six submarines of the Black Sea Fleet went to sea, which was an unprecedented event. Russian ground forces also started a buildup on the border with Ukraine. On 2 April, Zelensky had his first telephone conversation with Biden, and on 6 April he called NATO's Secretary-General Jens Stoltenberg pressuring NATO to speed up Ukrainian path to the membership. On 8 April, Russia started moving ten of its Caspian Flotilla warships to the Black Sea. Six amphibious and three artillery boats of Serna and Shmel classes, as well as a hydrographic boat GS-599, were reported in transit, while Black Sea Fleet frigate Admiral Essen conducted an artillery exercise, usually done to raise the readiness for the amphibious landing. The same day, the US decided to send two warships to the Black Sea. On 9 April 2021, tensions rose further and Ukraine promised not to attack the separatists, while Russia considered intervening to prevent bloodshed. On the same day, two Black Sea Fleet corvettes, Vishny Volochyok and Gravoron, conducted an exercise. The two US destroyers were clarified by Turkey to be USS Roosevelt and USS Donald Cook, while Putin stressed the importance of the Montreux Convention in a telephone conversation with Turkish president Recep Erdogan. On 14 April, the