Beijing sailed its aircraft carrier Shandong through the sensitive Taiwan Strait on Friday, a source with direct knowledge of the matter told Reuters. The transit, which came just hours before the Chinese and US presidents were due to talk, also saw the Shandong being shadowed by a US destroyer, the source said. Beijing claims democratically ruled Taiwan as its own territory, and has over the past two years stepped up military activity near the island to assert sovereignty claims, alarming both Taipei and Washington. The source, who was not authorised to speak to the media and spoke on condition of anonymity, said the Shandong sailed close to the Taiwan-controlled island of Quemoy, also known as Kinmen, which sits directly opposite the mainland city of Xiamen, and that it was shadowed by a US warship. “Around 10.30am the CV-17 appeared around 30 nautical miles to the southwest of Kinmen, and was photographed by a passenger on a civilian flight,” the source said, referring to the Shandong’s official service number. Taiwan holds live-fire drills on islet nearest mainland China The USS Ralph Johnson , an Arleigh-Burke guided missile destroyer, shadowed the Chinese carrier, which did not have aircraft on its deck and sailed north through the strait, the source added. Taiwan also sent warships to keep an eye on the situation, the source said. Taiwan’s defence ministry declined to comment, while Beijing and the US Navy did not immediately respond to requests for comment. The sailing came about 12 hours before US President Joe Biden was due to hold a telephone call with his Chinese counterpart, Xi Jinping. The source described the timing of the Shandong’s movement so close to that call as “provocative”. Beijing says Taiwan is the most sensitive and important issue in its relations with the United States. Washington has no formal diplomatic ties with Taiwan but is its most important international backer and arms supplier. The Shandong is China’s newest aircraft carrier, commissioned in 2019. China’s only other carrier, the Liaoning, is mostly used for training purposes.