TAIPEI (Taiwan News) — Taiwan's Indigenous Defense Fighter (IDF) jets spent half of their flight time in June monitoring incursions and approaches by Chinese warplanes, reports said Tuesday (July 28).

Aircraft from China’s People’s Liberation Army Air Force (PLAAF) repeatedly entered Taiwan’s Air Defense Identification Zone (ADIZ) over the past few months, specifically its southwestern corner, off the coast of Kaohsiung.

During a visit to the Tainan Air Force Base where the IDF jets are based, officials heard that half the missions in June were devoted to keeping an eye on Chinese jets over the middle of the Taiwan Strait or in the southwestern part of the ADIZ, and the other half were training flights, UDN reported.

In contrast to previous years, the Chinese warplanes more recently also appeared at night, in the evening, or even in the early morning. The Ministry of National Defense and the Air Force did not provide detailed commentary on the actions of the Chinese jets, only saying that they were closely monitoring all sea and air space surrounding Taiwan.