The SCSPI Research Institute in Beijing said US Hai Duong monitoring vessels have enhanced the operation of Chinese submarines in the South China Sea.

Organization monitoring the Strategic Sea Strategy (SCSPI) based in Beijing on July 13, said the US Hai Duong monitoring vessels followed at the East Sea at least 161 days in the first 6 months of the year

5 surveillance vessels that US uses include Victorious, Able, Effective, Loyal and Impeccable, anchoring in Japan.

The main purpose is to monitor China's underwater force, analyze the operating range of submarines in their significant sea and outgoing glands, and support intelligence for anti-implicit, reporting

US Victorious Hai Duong monitoring ship.

The scope of operation is mainly in the waters around the Paracel Islands of Vietnam and Macclesfield underground beach.

The SCSPI report was given after the comments of the Chinese Ministry of Foreign Affairs spokesman summoned Kien Kien on July 12.

Washington said such activities are needed to curb Beijing's claims.

China is supposed to own one of the world's largest submarine fleets.

The Pentagon's report in 2020 said China has 4 ballistic missiles, 6 attack submarines running by nuclear energy and 46 diesel engine submarines.