A diplomatic note has been given to representatives of the Chinese embassy in Hanoi to protest the Chinese vessel’s action in sinking the Vietnamese fishing boat and detaining the fishermen, Foreign Ministry spokeswoman Le Thi Thu Hang said in a statement Friday.

On Thursday, the Chinese vessel has rammed and sank the boat owned by Tran Hong Tho from the central province of Quang Ngai, with eight fishermen onboard while there were fishing off Woody (Phu Lam) Island in Vietnam’s Hoang Sa Archipelago (Paracel Islands) in the East Sea, known internationally as the South China Sea.

"Vietnam is asking China to investigate the incident and take strict action against the Chinese vessel and refrain from repeating such acts in future as well as pay proper compensation for the damage caused to the Vietnamese fishermen," Hang said.

"These actions of the Chinese vessel have infringed Vietnam's sovereignty over the Hoang Sa Islands and endangered the lives and properties of Vietnamese fishermen," she said.

China's actions also go against the common view of senior leaders of the two countries on treating fishermen humanely, and the Vietnam-China Agreement on Basic Principles Guiding the Settlement of Maritime Issues. They violate the Declaration on the Conduct of Parties in the South China Sea and negatively affects negotiations for a Code of Conduct in the waters, Hang said.

The move has increased tensions, caused destabilization and is not beneficial to the maintenance of peace, stability and cooperation in the region, she said.

Hang said Vietnam has full legal basis and historical evidence under international law for its sovereignty over the Hoang Sa (Paracel) and Truong Sa (Spratly) archipelagos.

The Vietnam Fisheries Society has also called on the Government Office, the Ministry of Foreign Affairs and other government agencies to ensure China pays compensation to Vietnamese fishermen for sinking their boats.

The Quang Ngai’s Fisheries Society said that after sinking the Vietnamese boat, the Chinese vessel had picked up eight Vietnamese fishermen and taken them to the Woody Island. Upon receiving news of the sunken ship, three other Vietnamese fishing boats tried to rescue then, but were chased by the Chinese vessel. Two of the vessels were captured and towed to the island.

At 2 p.m. Thursday, China released the two fishing boats and eight fishermen. A day later, Vietnamese authorities received the detained Vietnamese fishermen safely.

China seized the Paracel Islands from South Vietnam by force in 1974, and has since been occupying them illegally.

In 2014 China brought an oil rig, Haiyang Shiyou 981, and installed it in waters off the Paracel Islands, changing the status quo in the waters. Since then, Chinese ships have chased after and rammed many Vietnamese fishing vessels near the islands.