A statement by the Taiwanese defense ministry said its army’s Kinmen Defense Command discovered an “unidentified civilian drone” in restricted airspace off Shihyu. The Taiwan-controlled islet is only 2.5 miles from the Chinese city of Xiamen, where the device is thought to have originated.

The island’s soldiers, who were given new response protocols after multiple drone incursions in recent weeks, attempted to expel the unmanned vehicle after detecting it at 12:03 p.m. local time, and ultimately fired upon it to bring it down into the sea, the ministry said.

In a busy August that saw Chinese forces ramp up military exercises around Taiwan in dramatic fashion—in a stated response to U.S. House Speaker Nancy Pelosi’s visit to the island—Taipei said it had dealt with a number of civilian drone incursions on its outlying Kinmen and Matsu islands, both of which lie on the far side of the Taiwan Strait near China.

Taiwan had deliberated equipping frontline forces near China with anti-drone weaponry following the initial airspace incursions last month. However, the command post didn’t say what type of weapon was used to bring down Thursday’s drone. Live rounds were fired to warn off four drones between Tuesday and Wednesday, its statement said.

The operators of the drones were never identified; neither were their make or model. Hobbyist devices, however, have an effective transmission range of several miles—more than enough to reach Taiwan’s offshore outposts.

Taiwanese officials say the Chinese military may be using commercial drones to probe defenses as part of a hybrid strategy that avoids direct conflict.

At least two videos circulating on China’s social media websites showed startled Taiwanese troops watching the drones fly overhead. In one instance, a soldier outside a guard post pelts a drone with stones. Officials in Beijing, meanwhile, have not claimed responsibility for the alleged actions.

During a recent visit to Penghu, a group of islands closer to Taiwan, President Tsai Ing-wen said the drones were part of China’s “gray zone” psychological warfare against the island’s public.

“The more provocative the enemy is, the more calm we must be. We will not give the other side an inappropriate excuse to create conflict. We will not provoke disputes, and we will exercise self-restraint, but that does not mean we will not respond,” she said.

John Kirby, spokesperson for the U.S. National Security Council, said Wednesday: “We’ve certainly noted the reports coming out of Taiwan about the overflight.”

“The concerns expressed by leaders in Taiwan are understandable given the aggressive, assertive, coercive, and quite frankly, unnecessary, activities that the [People’s Republic of China] continues to conduct from a military perspective in and around the strait,” Kirby said.

Beijing was attempting to change the status quo around Taiwan by setting “a new normal for their activities and behaviors,” and that the United States would not “recognize it” or “abide by it,” Kirby said.

The U.S. Navy sailed two guided-missile cruisers through the Taiwan Strait over the weekend.