TAIPEI (Taiwan News) — Taiwan's Ministry of National Defense (MND) tracked four Chinese military aircraft and four naval vessels around the country between 6 a.m. Wednesday (May 1) and 6 a.m. Thursday (May 2).

The defense ministry said that four People’s Liberation Army (PLA) fighter jets had been detected in the Taiwan Strait. The MND said the fighters crossed the median line and entered the northern and southwestern air defense identification zone (ADIZ).

Three of the PLA aircraft crossed the median line and entered the southwest ADIZ and came within 255 km (138 NM) of Eluanbi. One of the fighters entered the northern ADIZ and came within 142 km (77 NM) of Keelung. 

The ministry said it monitored the situation with its intelligence, surveillance, and reconnaissance systems and scrambled combat patrol aircraft, dispatched naval vessels, and deployed land-based air defense missile systems.

Since September 2020, Beijing has increasingly employed the use of "gray zone tactics" in the form of deployments of military aircraft and naval vessels over the median line and inside Taiwan's ADIZ.

According to CSIS, gray zone tactics are “an effort or series of efforts beyond steady-state deterrence and assurance that attempts to achieve one’s security objectives without resorting to direct and sizable use of force."