Taiwan’s defense ministry on Sunday announced a five-day combat readiness exercise as China intensifies military activity around the island.

The announcement came as Taiwanese authorities said 21 Chinese aircraft, including fighter jets and surveillance planes, were operating near Taiwan, which Beijing considers a renegade province.

Taipei’s drills will simulate a scenario where China abruptly escalates one of its military exercises into an actual attack.

Taiwan is now almost always surrounded by five or six Chinese warships, The Wall Street Journal reported.

Analysts say the deployments allow Beijing to collect intelligence on Taiwan’s forces and operating patterns as it builds capabilities for a potential conflict.

China’s leader has directed the military to be prepared for a possible Taiwan takeover by 2027.