Taiwan was forced to scramble its fighter jets on Sunday to intercept a squadron of Chinese aircraft that entered its air defense zone. Taiwan’s Defense Ministry said that 27 Chinese aircraft breached its defense zone in its latest incursion. The incident comes as Chinese President Xi Jinping met with his top generals.

 China’s air force has been conducting flights near Taiwan’s democratically administered island for the past months, frequently in the southwestern area of its air defense identification zone, or ADIZ, close to the Taiwan-controlled Pratas Islands.

Taiwan refers to China’s frequent military activity in the vicinity as “gray zone” warfare, which is intended to wear down Taiwan’s troops by forcing them to scramble repeatedly, as well as to test Taiwan’s countermeasures.

Over a four-day period beginning on October 1, when China celebrated its national day, Taiwan said nearly 150 PLA military aircraft entered its ADIZ, which is a broader area Taiwan monitors and patrols to give it more time to respond to any threats. The ADIZ is not territorial air space.

According to the Taiwan Ministry of Defense, the newest Chinese operation featured 18 fighter jets, five nuclear-capable H-6 bombers, and an unexpected Y-20 aerial refueling aircraft.

Taiwan dispatched combat aircraft to warn the Chinese planes, while missile systems were deployed to keep an eye on them. China did not respond immediately, despite previously claiming that similar actions were drills intended at defending the country’s sovereignty.

While the incident was unfolding, China’s president was reportedly holding a three-day meeting with the nation’s top officials. The meeting was to discuss how China could further strengthen its military forces through talent cultivation. While Xi did not specifically address Taiwan in his speech, he did emphasize the necessity to upgrade the military in order to win any future conflicts.