TAIPEI (Taiwan News) – Four Chinese military aircraft of different types entered Taiwan’s air defense identification zone (ADIZ) from the southwest on Wednesday (Dec. 16), according to military sources.

The aircraft were a Y-8 anti-submarine plane, a Y-8 electronic intelligence plane, a Y-9 electronic warfare aircraft, and a Y-8 reconnaissance plane, CNA reported.

As on previous occasions, Taiwan’s Air Force scrambled jets and issued radio warnings to tell the People’s Liberation Army Air Force pilots to turn back. Air defense missile systems were also deployed to monitor the four aircraft’s activities in the area, the Ministry of National Defense said.

The country has been facing incursions into its ADIZ on an almost daily basis for months, as the Chinese government follows a policy of intimidating Taiwan and its potential allies, observers said.