TAIPEI (Taiwan News) — Two Shenyang J-16 fighter jets from the People’s Liberation Army Air Force (PLAAF) intruded into Taiwan’s air defense identification zone (ADIZ) on Saturday (Dec. 4), according to the Ministry of National Defense.

As on most previous occasions, the intrusions occurred in the zone’s southwest section, between Taiwan’s main island and the disputed Taiwanese-held South China Sea islands of Dongsha and Taiping. The ministry started publicizing the incursions on its website in September 2020.

The most active period for PLAAF activity close to Taiwan was in early October 2021, CNA reported. On Oct. 1, China’s National Day, 38 military aircraft entered Taiwan’s ADIZ, including 10 J-16 jets. On Oct. 2, 39 Chinese planes were spotted, on Oct. 3 there were 16 aircraft, and on Oct. 4 a record number of 56 PLAAF airplanes were reported.

On Saturday, Taiwan’s Air Force sent aircraft, issued radio warnings and deployed air defense missile systems to monitor the Chinese activities. Beijing’s behavior has caused concern in the United States, Japan, and other democracies as they fear China might be preparing for an invasion of Taiwan, a move U.S. Secretary of State Antony Blinken has warned against.