Five J-16 fighters and four Y-8 reconnaissance planes of different variants were among the People’s Liberation Army Air Force assets to violate Taiwan’s self-declared air defense identification zone (ADIZ), according to the ministry. It illustrated the flight paths on its website and said it had tasked interceptor jets and tracked the Chinese aircraft using missiles.

Local enthusiasts monitoring Taiwan’s airwaves told Newsweek that the Republic of China Air Force issued seven radio warnings to China’s warplanes between 08:52 a.m. and 5:32 p.m. Taipei time. The majority of warnings go unanswered, but there have been some notable PLAAF responses in recent weeks.

Tuesday marked the 17th day this month that PLA warplanes had flown into Taiwan’s ADIZ, with most incursions occurring in the southwest corner, south of the Taiwan Strait and near the mouth of the South China Sea. Between January and March, the island’s Ministry of National Defense reported 27, 17 and 18 days of ADIZ violations.

However, a comparison of the total aircraft figures shows the more concerning side of what analysts have described as China’s “gray-zone warfare” against Taiwan.

Beijing sent 69 planes toward the Chinese-claimed island nation last September, the month Taipei first began publicly reporting ADIZ violations. Chinese military intimidation against Taiwan rose in January with 81 total sorties—a response to perceived “provocations” by former President Donald Trump and later newly inaugurated Joe Biden—before falling to 40 and 54 in February and March respectively.

The PLAAF shattered the ceiling this month with 96 sorties thus far, bringing the yearly total to 269 as of April 20—already 70 percent of the 380 total aircraft detected in 2020. Last Monday, the Chinese military also set a record for single-day aircraft intrusions, flying 25 warplanes into Taiwan’s ADIZ after the State Department announced new guidelines for interactions between Taipei and Washington.

A March defense ministry report prepared for Taiwan’s lawmakers revealed that ROCAF pilots had flown an additional 1,000 hours in order to deter Chinese warplane intrusions last year.

Taiwan’s top national security minds have likened Beijing’s gray-zone tactics—encompassing all measures short of war—to a form of psychological warfare, which goes hand-in-hand with disinformation campaigns and targeted cyberattacks.

China’s use of the PLA to intimidate Taiwan tends to spike during perceived improvements to U.S.-Taiwan relations, experts say. The military operations in the Taiwan Strait also serve as attempts to tax the island’s outnumbered air force and pile pressure on the Taiwanese government to accept Beijing’s preferred regional arrangement, one in which democratic Taiwan is subsumed into the mainland as a province.

In the meantime, President Tsai Ing-wen continues to receive bipartisan support on Capitol Hill and will look to the United States—her country’s most important international backer—to help bolster Taiwan’s self-defense capabilities.

When Taiwan begins the first phase of its annual Han Kuang military exercise this Friday, before following it up with live-fire drills in July, members of the ruling Democratic Progressive Party say the island will be looking to present an image of determination and a state of preparedness in the face of an existential threat from across the strait.