The sailing happened about 12 hours before US President Joe Biden is due to speak to his Chinese counterpart, Xi Jinping.
The source described the timing of the Shandong’s movement so close to that call as “provocative”, and that it was unusual it sailed during daylight hours, with previous missions happening at night.
Last April, China’s navy said a carrier group, lead by the Liaoning, the country’s first aircraft carrier put into active service, was carrying out routine drills in the waters near Taiwan.
Taiwan is already in a heightened state of alert due to the Ukraine war, wary of China taking advantage of the situation to make a move of its own, though there have been no signs Beijing is about to mount any kind of military strike.
Lo Chih-cheng, a senior lawmaker from Taiwan’s ruling Democratic Progressive Party called the Shandong’s transit a “very provocative message” when countries in the region are already alarmed by the war in Ukraine and hours before the Biden-Xi call.
“Tensions across the Taiwan Strait won’t rise sharply because of this, but it will likely cause neighbouring countries to raise their military alert level,” he told Reuters.
China says Taiwan is the most sensitive and important issue in its relations with the United States. Washington has no formal diplomatic ties with Taipei, but is Taiwan’s most important international backer and arms supplier.
Taiwan rejects China’s sovereignty claims and has repeatedly vows to defend its freedom and democracy.
Kuo Yu-jen, a security expert at Taiwan’s National Sun Yat-sen University, said the Shandong was likely to be on its way up to northern China for next month’s celebrations marking the founding of China’s navy.
“It was carrying no aircraft and had no frigates” accompanying, he added.
The Shandong is China’s newest aircraft carrier, commissioned in 2019.
In December 2019, shortly before presidential and parliamentary elections in Taiwan, the Shandong sailed through the Taiwan Strait, a move condemned by Taiwan as attempted intimidation.
Taiwan’s air force also scrambles aircraft almost daily to see off Chinese warplanes flying into Taiwan’s air defence identification zone, mostly to the southwestern part of the strait at the top end of the South China Sea.
Taiwan calls this “grey zone” warfare activity, designed to both test its responses and wear out Taiwan’s air force.