SHANGHAI/TAIPEI (Reuters) - China’s military tailed a U.S. warship as it passed through the sensitive Taiwan Strait on Saturday, the Chinese military said, denouncing such missions as sending “flirtatious glances” to supporters of Taiwan independence. China, which claims democratically-run Taiwan as its own territory, has been angered by stepped-up U.S. support for the island, including arms sales and sailing warships through the Taiwan Strait, further souring Beijing-Washington relations. The U.S. Navy said the guided missile destroyer USS Mustin had conducted “a routine Taiwan Strait transit (on) Dec. 19 in accordance with international law”. “The ship’s transit through the Taiwan Strait demonstrates the U.S. commitment to a free and open Indo-Pacific,” it added. This is the 12th sailing through the strait by the U.S. Navy this year. China’s military, in a statement released by its Eastern Theatre Command, said its air and naval forces “tailed and monitored” the vessel throughout. Such missions “deliberately raise the temperature of the Taiwan issue, as they fear calm in the Taiwan Strait, and send flirtatious glances to Taiwan independence forces, seriously jeopardising peace and stability in the strait”, it said. The United States is engaging in a show of force and trying to use Taiwan as a pawn for its own selfish strategic purposes, the statement added. In Taipei, Taiwan’s Defence Ministry said the U.S. ship had proceeded in a southerly direction, that it has also monitored its movements, and that “the situation was as normal”. Beijing believes Taiwan President Tsai Ing-wen is bent on a formal declaration of independence for the island, a red line for Beijing. She says Taiwan is already an independent country called the Republic of China, its formal name. Tsai has made bolstering Taiwan’s armed forces a priority in the face of repeated Chinese military activity near the island, including on occasion this year sending fighter jets across the Taiwan Strait’s median line, an unofficial buffer.