The Taiwanese Defense Ministry said on Thursday it detected 66 Chinese warplanes and seven Chinese naval vessels circling the island during the previous 24 hours, marking the largest Chinese incursion into Taiwan’s Air Defense Identification Zone (ADIZ) in 2024.

Taiwanese officials said 56 of China’s planes crossed the median line of the Taiwan Strait, which was once considered an informal buffer zone that neither side would cross to avoid misunderstandings and conflict escalation. China publicly stated in April 2023 that it would no longer respect the median line.

The Taiwanese Defense Ministry noted that some of China’s ships and planes were apparently on their way to a military exercise involving the aircraft carrier Shandong. At the very least, the People’s Liberation Army Navy (PLAN) did not go out of its way to avoid passing through Taiwan’s ADIZ while mustering its forces for the naval exercise.

The Defense Ministry published some photos of China’s aircraft, including the advanced J-16 Hidden Dragon strike fighter and the nuclear-capable H-6 bomber.

“The military has a detailed grasp of the activities in the seas and waters around the Taiwan Strait, including of the Chinese Communists’ aircraft and ships,” the ministry said, without indicating if the photos were new pictures taken on Wednesday.

Military expert Su Tzu-yun of Taiwan’s Institute for National Defense and Security Research noted that the incursions on Wednesday and Thursday were the largest since China petulantly staged aggressive military exercises in May to “punish” the island for electing William Lai Ching-te as president.

Su told Voice of America News (VOA) that China might be in punishment mode again, reacting angrily to Lai’s meeting on Wednesday with Raymond Greene, the new director of the American Institute in Taiwan (AIT). The AIT informally serves as the U.S. embassy to Taiwan, making Greene the new de facto ambassador.

Greene told Lai the United States is committed to enhancing the “already rock-solid” ties between America and Taiwan and helping Taiwan defend itself. Su suggested China sent its warplanes and ships around Taiwan to “express its displeasure” at the support Taipei enjoys.

Taiwanese Defense Minister Wellington Koo added the observation that when China sent the aircraft carrier Shandong to join the PLAN exercise, it did not pass through the Bashi Channel, the route south of Taiwan normally used by Chinese ships heading for the Pacific. Instead, the carrier used the more southerly Balingtang Channel route, which took it close to the Philippines — another neighbor China has been working hard to intimidate lately.