US reconnaissance and transport aircraft yesterday flew over the Ba Si Strait, south of Taiwan, in the island's air defense identification zone.

"On the morning of June 25, US P-8A and RC-135 aircraft conducted reconnaissance operations in the South China Sea, focusing on the eastern sea area of the Strait of Poland, while a C-17A Globemaster III mechanical transport.

The flight image published by SCSPI shows that US reconnaissance and transportation of aircraft are from Okinawa, Japan.

The P-8A reconnaissance then separated, flying towards the Dong Sa archipelago, where Taiwan deployed its coast guard and marines, before approaching the southeastern coast of mainland China.

Dongsha language project between the bases of China on Hainan Island and Pacific, so the archipelago is strategically important for the Chinese navy.

Taiwan has yet to comment on US aircraft operations near the island.

Taiwan's defense agency, however, said yesterday that the Su-30, J-10 and Y-8 fighter aircraft of the People's Liberation Army (PLA) of China 11 times approached the island in June,

Ba Si Strait (highlighted in red).

Experts say the P-8A reconnaissance in the area indicates that the US may be paying close attention to the activity of Chinese nuclear submarines near the Philippine Sea.

"If China deploys submarines through the Strait of Ba Si and Balintang, between Taiwan and the Philippines, they will deter US naval operations between the South China Sea and the Philippine Sea," said Alexander Huang Chieh-cheng, professor.

Huang said such submarine deployments were intended to "demonstrate the intention to gain greater control" over the waters between China and the entities on Bohai, Yellow Sea, East China Sea and South China Sea.