HONG KONG—Dozens of Chinese military aircraft and navy vessels were detected around Taiwan early Friday, including one that flew around the island, Taipei’s Ministry of National Defense said.
The 38 warplanes and six ships represented the biggest deployment since China sent 91 aircraft and a dozen vessels to greet Taiwan President Tsai Ing-wen the day after her return from a visit to the U.S. this month. China’s Communist Party claims Taiwan, a self-ruling island, as part of its territory and had strongly protested Ms. Tsai’s visit.
Taiwan’s Defense Ministry said half the aircraft Friday crossed the median line that serves as a de facto demarcation with mainland China across the roughly 100-mile-wide Taiwan Strait. In the first publicly acknowledged maneuver of its kind, one combat drone flew around the island within what Taipei claims as its air defense zone, international airspace that a government monitors and exercises control over in the interest of its national security. Another unmanned reconnaissance vehicle flew halfway around before doubling back, according to maps the ministry released.
The maps showed a flight path that began with the incursion across the median line to the southeast of the island and then traced a path around the coastline before exiting across the median line in the northeast.
Taiwan’s armed forces monitored the situation and ordered combat air patrols, navy vessels, and operators of its land-based missile systems to respond to the activities, the Defense Ministry said.
In recent years, the Chinese military, the People’s Liberation Army, has engaged in increasingly bold maneuvers around Taiwan. Two years ago, it would have been a major political event if any Chinese warplane crossed the median line, according to Wen-ti Sung, a political scientist at Australian National University who studies ties among Washington, Beijing and Taipei.
Now the crossings happen almost daily, Mr. Sung said.
Many of the incursions involve rapid dips in and out of Taiwan airspace that test its defenses, and are primarily viewed as a method of political signaling while also allowing the PLA to gain operational experience, China military analysts have said.
Since the beginning of the year, Taiwan’s Defense Ministry has also publicly confirmed six other drones flying halfway around the island before doubling back, including once by a combat drone, the ministry’s maps show.
China’s Taiwan Affairs Office didn’t immediately respond to a faxed request for details of the PLA’s operations around Taiwan.
These gradual qualitative changes, including the latest escalation, are the PLA “chipping away at norms bit by bit,” Mr. Sung said.
Also on Friday, the Chinese military’s Eastern Theater Command denounced a U.S. anti-submarine patrol aircraft transiting through the Taiwan Strait, calling it a provocative action.
Mr. Sung said the PLA’s Friday maneuver doesn’t suggest a change in Beijing’s strategy toward Taiwan. “Beijing top level leadership is still showing signs that it’s interested in being a rational strategic actor,” he said. It would rather prioritize a peaceful reunification using tactics such as election interference over a military-led, coercive one, he said.
China’s displays of aggression toward Taiwan can also backfire, hardening opposition within the island as well as raising concerns in regional capitals.
Earlier this month, the U.S. and the Philippines held their largest annual joint military drills, following China’s three-day military display in response to Ms. Tsai’s U.S. trip.
President Biden has repeatedly stated that the U.S. would defend Taiwan from a Chinese attack, though official American policy still maintains “strategic ambiguity” on the issue to avoid escalating hostilities.
Military analysts say the U.S. struggles to produce weapons and submarines, meet recruitment goals as well as come up with new ways of waging war, making it ill-equipped to handle a conflict with China.
The U.S.-Philippines drills, involving more than 17,500 troops, ended less than flawlessly this week when a High Mobility Artillery Rocket System, or Himars, rocket launcher failed to hit its target with all six of its rockets.
Write to Karen Hao at karen.hao@wsj.com