On 28 December 2005, a third Russian-built Sovremenny -class destroyer was delivered to the Chinese PLA Navy. The destroyer, named Taizhou , was launched in April 2004 and is shown soon after delivery. Built to a slightly modified design than the original two units in Chinese service, the Taizhou and a soon-to-be-delivered sister ship reportedly have improved surface-to-air missile systems and an upgraded, longer-range variant of the SS-N-22 antiship missile. The destroyers are primarily intended for surface warfare tasks, including antiship, shore-bombardment, and antiair defense. The fourth Sovremenny -class destroyer is expected in service by the end of this year. All four will likely be based at Zhoushan Naval Base as part of China's East Sea Fleet. In addition to the four destroyers purchased from Russia, China is building a large number of new warships domestically, including new Project 052C destroyers, Jiangwei -II-class and Project 054 -class frigates, and new amphibious assault ships, along with three classes of conventionally-powered and two types of nuclear-powered submarines.