Two United States destroyers conducted a rare double-ship Taiwan Strait transit on the last day of 2020, as their Chinese counterparts kicked off massive naval exercises in the disputed South China Sea . It was the 13th mission through the sensitive strait in 2020 but the first time in the year that the US had sent double destroyers there, according to Beijing-based think tank the South China Sea Strategic Situation Probing Initiative. Military experts suggested that the transit could be related to ongoing large-scale naval exercises by China’s People’s Liberation Army (PLA) involving its aircraft carrier Shandong and other warships in the South China Sea. China’s maritime authority said the PLA was conducting three 10-day exercises simultaneously off the southern Chinese island of Hainan, beginning on Tuesday this week. The American transit was announced by the US Seventh Fleet on its Facebook page, where it said two Japan-based guided-missile destroyers, USS John S. McCain and USS Curtis Wilbur, had “conducted a routine Taiwan Strait transit [on] December 31 in accordance with international law”. It drew an immediate rebuke from the Chinese defence ministry, which said it was “provocation” and sent “wrong signals” to supporters of Taiwan independence, amounting to a serious threat to peace and stability. The Beijing government views the self-ruled Taiwan as its own territory, to be brought into its fold by force if necessary, and has been angered by increased US support for the island, including arms sales and sending warships. Thursday’s mission was the second time US warships had sailed through the strait in three weeks, according to the US Navy. The USS Mustin guided-missile destroyer demonstrated “the US commitment to a free and open Indo-Pacific” on December 19, according to the US Seventh Fleet. China’s Shandong carrier then passed through the strait the following day . “It’s predictable that the US warships would come because all the PLA Navy’s exercises have taken place in the South China Sea to catch up on year-end drill missions,” Chinese military expert Zhou Chenming said, adding that a potential alternative location, Bohai Bay in northeast China, was frozen. Collin Koh, a research fellow from the S. Rajaratnam School of International Studies in Singapore, said it was expected that the two militaries would step up activities in the region. “There’s no abating of the tensions between the US and China, especially given the stepping up of measures against Beijing by the Trump administration in its final days in office,” Koh said. “Both militaries want to demonstrate that even amid the festivities, they remain operationally ready. So this posturing and counter-posturing is designed to signal resolve.” Former PLA instructor Song Zhongping said it was “quite rare for the US military to send two destroyers” when the PLA was staging exercises. “The high-profile voyage indicated the US had accelerated its efforts to sail through the Taiwan Strait, making the transit a routine operation, to put more pressure on the PLA,” Song said. The Shandong, China’s first home-built carrier, is soon expected to reach initial operational capability, the basic level of combat readiness, possibly in early 2021.