A missile is launched during the PLA air force's "Blue Shield-17S" drill competition on October 28, 2017. Photo: 81.cn

China on Thursday kicked off a two-and-a-half month series of military exercises on the northern coast. The drills are more likely to be a regular period of internal training aimed at boosting the combat ability of the People's Liberation Army (PLA) and putting its advanced air defense weapons to the test, rather than targeting the island of Taiwan as some reports by Taiwan media have suggested, analysts said.

From Thursday to July 31, live-fire shooting will be conducted in the northeastern sea areas off Tangshan, North China's Hebei Province, read a navigation restriction notice the Maritime Safety Administration released on its website on Monday.

According to the coordinates and descriptions provided in the notice, the restricted zone is a fan-shaped area with a radius of 25 kilometers, about 525 square kilometers in total, covering some coastal land areas but mostly sea areas.

All unrelated vessels and personnel should stop all activity in this area during this period and evacuate to safe zones in advance to avoid accidents, the notice said.

The Chinese military has not announced any details of the drills, and speculation soon arose over the exercises, which have an extended duration.

Taiwan media outlet EBC News on Wednesday related the drills to Taiwan regional leader Tsai Ing-wen's scheduled inauguration speech on May 20, which is only one week away.

Some reports claimed the drills could feature landing exercises with the aim of enhancing the ability of the PLA to reunify the island by force.

China Central Television (CCTV) military program Weihutang reported on Tuesday that the exercises are being held in the Bohai Bay, the maritime gateway to the nation's capital Beijing, and a strategically important location to protect Beijing, Tianjin and Hebei.

The PLA has previously held multiple "Blue Shield" series air defense exercises in this region, during which it tested the technical and tactical capabilities of some new types of air defense missiles, Weihutang reported.

The Bohai Bay is also one of China's naval weapon test zones, and a training base for aircraft carrier-based fighter jets is located nearby, Weihutang noted.

Judging from the location, time and area, the drills are likely regular and internal exercises of the PLA, Xu Guangyu, a senior adviser to the China Arms Control and Disarmament Association, told the Global Times on Thursday.

If the PLA wanted to send a warning to Taiwan secessionists, the drills would not be held in an inland sea area like the Bohai Bay, but would be conducted in the Huanghai Sea, East China Sea or South China Sea, which are nearer to Taiwan, Xu said, noting that the drill zone is not that large and the extended period may indicate tests of new weapons.

Tests of large weapons like the JL-3 submarine-launched ballistic missile are also unlikely, because the location is too near to land, analysts said.

Taiwan secessionists knew they were doing wrong and had a guilty conscience, so they actively related the drills to themselves, a military expert who asked not to be identified told the Global Times on Thursday.

They should always fear the PLA because it has the capability and determination to solve the Taiwan question by force at any time as necessary, regardless of whether it is holding these specific drills to warn them, the expert said.