A J-10 fighter jet attached to an aviation brigade of the air force under the PLA Southern Theater Command takes off for a round-the-clock flight training mission on November 8, 2022. (eng.chinamil.com.cn/Photo by Wang Guoyun)

Fighter jets of the Chinese People's Liberation Army (PLA) reportedly approached the 24-nautical-mile line of the island of Taiwan on Saturday, a move experts said on Sunday is totally legitimate and will become more frequent if "Taiwan independence" secessionist forces continue to provoke.

The defense authority on the island of Taiwan said on Sunday morning in a press release that it had detected 21 PLA aircraft and five PLA vessels around the island over the past 24 hours, including eight J-10 fighter jets that had crossed the so-called median line of the Taiwan Straits.

The median line is a non-existent concept dividing the two sides of the Taiwan Straits from the middle and the median line is never recognized by the Chinese mainland.

According to flight paths illustrated in the press release, the eight J-10 fighter jets flew past the "median line" from four locations covering the northern and southern ends as well as the middle of the Taiwan Straits before returning to the mainland.

Going beyond the so-called median line, the warplanes approached the 24-nautical-mile line of the island, the island's defense authority said on Saturday shortly after the aircraft activities, media on the island reported, claiming that it marked the first time that PLA aircraft have approached the island of Taiwan's 24-nautical-mile line.

The 24-nautical-mile line is often used to describe the contiguous zone, which can extend up to 24 nautical miles from the baseline, while the territorial sea can extend up to 12 nautical miles from the baseline, a Chinese mainland military expert told the Global Times on Sunday, requesting anonymity.

The defense authority on the island of Taiwan might want to use the concept of a contiguous zone to hype "threats" from the PLA, but Taiwan is an inseparable part of China, so it is legitimate for the PLA to operate anywhere on and around the island, the expert said.

Fu Qianshao, a Chinese mainland military aviation expert, told the Global Times that routine sorties by PLA warplanes serve as stern warnings to "Taiwan independence" secessionist forces and external interference forces.

The PLA has demonstrated its capabilities in safeguarding national sovereignty, security and development interests, Fu said.

The PLA has been holding daily aircraft and vessel patrols and exercises around the island of Taiwan for the past few years.

If "Taiwan independence" forces do not give up their secessionist moves, the PLA's activities will become closer to the island, more frequent and more combat-oriented, analysts said.