TAIPEI (Taiwan News) — The defense ministry detected 11 Chinese military aircraft, six naval vessels, and two official ships around Taiwan between 6 a.m. on Saturday and Sunday.

All of the aircraft were reported to have crossed the median line of the Taiwan Strait and entered the eastern and southwestern areas of the country’s air defense identification zone, or ADIZ. Three Chinese balloons were also detected.

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 373 times and ships 157 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.”