The Chinese People's Liberation Army (PLA) monitored a group of warships from Australia, New Zealand, and Japan as they sailed through the Taiwan Strait. Experts believe the transit was a political stunt.

The Australian destroyer HMAS Sydney, the New Zealand supply ship HMNZS Aotearoa, and the Japanese destroyer JS Sazanami passed through the Taiwan Strait on Wednesday. The PLA tracked and monitored the ships throughout their transit.

Chinese Foreign Ministry spokesperson Lin Jian stated that the Taiwan question concerns China's sovereignty and territorial integrity. It is the political foundation of China-Japan relations and a red line that must not be crossed.

The Chinese military has handled in accordance with laws and regulations the entering into the Taiwan Strait of a Japanese Maritime Self-Defense Force vessel. China is highly vigilant on Japan's political intention behind this move and has protested to the Japanese side, Lin said.

On Australian and New Zealand warships' Taiwan Strait transit on Wednesday, Lin said China handles foreign warships' transit through the Taiwan Strait in accordance with laws and regulations, and meanwhile we stay vigilant against any acts that might jeopardize China's sovereignty and security.

The Taiwan Strait transit by these three countries is clearly a political stunt, aimed at flaunting their so-called solidarity while sending the wrong signal to "Taiwan independence" forces, Fu Qianshao, a Chinese military expert, told the Global Times on Thursday.

They are hyping their passage in the name of "freedom of navigation," aiming to show off and flex their military muscle, playing the "Taiwan card" targeting China, analysts said.

It is completely legitimate for the PLA to track and monitor foreign warships passing through the Taiwan Strait, experts said, noting that the PLA is ready at all times to deal with any potential emergencies.

Following the passage, the three countries' navies were scheduled to hold joint exercises in the South China Sea starting on Thursday, Reuters reported.

The exercise will not contribute to peace and stability in the region, observers said.

The South China Sea has been a tranquil region with busy sea lanes for international shipping, and such an exercise by countries from outside of the region is stirring up troubles and sabotaging freedom of navigation and security in the South China Sea, Fu said.