Chiu Kuo-cheng told members of the Legislative Yuan, Taiwan’s parliament, that he had redefined what constituted a first strike in order to account for a spike in the Chinese military’s unmanned aerial vehicle (UAV) activity around the island.

“The Chinese Communist Party is changing [its approach]. In the past, we defined a first strike as a missile or artillery [attack], but its UAVs are now frequently crossing the line, even flying overhead. This has caused a lot of trouble,” Chiu said.

“I’m treating a physical [intrusion] by a UAV as a first strike. This is our definition. Both sides are adjusting. There’s no major change,” he said, without elaborating what countermeasures would be authorized if a Chinese aircraft crossed into Taiwan’s 12-nautical mile territorial airspace.

Taiwan has never detected any Chinese military drones over its territory. Taiwanese troops stationed on front-line islands near the Chinese coast reported overflights by commercial drones in August and September, but the devices were never formally linked to China’s People’s Liberation Army (PLA).

Chiu issued new response protocols that resulted in a Chinese civilian drone being shot down for the first time in September.

PLA air force and naval patrols around Taiwan have increased since China conducted a week of high-intensity war games in the first week of August in response to House Speaker Nancy Pelosi’s visit to the island.

Chiu’s latest comments came shortly after a ruling party lawmaker pressed him last week on the Chinese military’s elevated level of activity in the region.

Taiwan’s defense chief acknowledged that China had created “a new normal” in the Taiwan Strait—to include an uptick in UAV flights—but he insisted Beijing’s forces wouldn’t be given free rein.

“Of course, we have a red line,” he said.

In a National Day address on Monday, President Tsai Ing-wen of Taiwan said her country had “no room for compromise” when it came to Taiwan’s “national sovereignty and our free and democratic way of life.”

“I want to make clear to the Beijing authorities that armed confrontation is absolutely not an option for our two sides,” she said.

Ma Xiaoguang, a spokesperson for the Taiwan Affairs Office in Beijing, said the contents of Tsai’s speech exaggerated China’s threat to the island.

China claims Taiwan as its own and refuses to renounce the use of force to achieve its objective of a political union with the island. Beijing’s offer to govern Taiwan under a Hong Kong-style “one country, two systems” model has been roundly rejected by the Taiwanese public and its president.

Chiu, Taiwan’s defense minister, told reporters before appearing in parliament on Tuesday: “China is using combat patrols as a pretext to conduct non-stop maneuvers in and around the Taiwan Strait. Yesterday alone, there were more than 20 aircraft in the area, eight of which crossed into [Taiwan’s] flight information region. If this isn’t provocative, then what is provocative?”

“Both sides, especially Taiwan, should exercise restraint, avoid disputes and avoid raising tensions,” he said. “Our side is trying hard.”