TAIPEI (Taiwan News) — The defense ministry detected 12 PLA aircraft and eight naval vessels around Taiwan between 6 a.m. on Friday and Saturday.

Nine aircraft were reported to have crossed the median line of the Taiwan Strait and into the nation’s southwestern and eastern air defense identification zone, or ADIZ. In response, Taiwan sent aircraft and naval ships and deployed coastal-based missile systems to monitor Chinese activity.

So far this month, Taiwan has tracked Chinese military aircraft 163 times and ships 67 times. Since September 2020, China has increased its use of gray zone tactics by incrementally increasing the number of military aircraft and naval vessels operating around Taiwan.

CSIS defines gray zone tactics as “an effort or series of efforts beyond steady-state deterrence and assurance that attempts to achieve one’s security objectives without resort to direct and sizable use of force.”