deployment of the two US destroyers was cancelled. On 17 April, amphibious ships Aleksandr Otrakovsky and Kondoponga of the Northern Fleet and Kaliningrad and Korolyov of the Baltic Fleet strengthened the amphibious warfare capabilities of the Black Sea Fleet. On 30 April, the cruiser Moskva fired a Vulkan anti-ship missile for the first time. In November, further tensions started amidst the build-up of Russian ground forces on the Ukraine border. On 2 November, the destroyer USS Porter entered the Black Sea, followed on 25 November by the destroyer USS Arleigh Burke. In late October, the Russian Black Sea fleet held a large exercise with a cruiser, a frigate and three corvettes. Incident with HMS Defender On 23 June 2021, the United Kingdom's undertook a freedom of navigation patrol through the disputed waters around the Crimean Peninsula. The Ministry of Defence of the Russian Federation and border guards said they fired warning shots from coast guard patrol ships and dropped bombs from a Sukhoi Su-24 attack aircraft in the path of Defender after, according to the Russian Defence Ministry, it had allegedly strayed for about 20 minutes as far as 3 km (2 miles) into waters off the coast of Crimea, which Russia annexed in 2014 in a move mostly unrecognised internationally. The UK military denied any warning shots were fired and said the ship was in innocent passage in Ukraine's territorial sea, later clarifying that heavy guns were fired three miles astern and could not be considered to be warning shots. 2022 Russian invasion of Ukraine A build-up of Russian forces around Ukraine and in Belarus began toward the end of 2021, ostensibly for exercises. In February 2022, the Black Sea Fleet was reinforced by six landing ships: three Ropucha-class vessels (Minsk (127), Korolev (130) and Kaliningrad (102)) were drawn from the Baltic Fleet while two (Georgy Pobedonosets (016) and Olenegorsky Gornyak (012)) came from the Northern Fleet. The Ivan Gren-class landing ship, Pyotr Morgunov (117) also deployed to the Black Sea from the Northern Fleet. The 22nd Army Corps (subordinate to the Black Sea Fleet) was also reinforced, including by the 247th Regiment of the 7th Guards Mountain Air Assault Division as well as by the 56th Guards Air Assault Regiment, subordinate to the same division. On the eve of the conflict, it was reported that the headquarters of the 58th Combined Arms Army had deployed to Crimea commanding