"We consider China bringing Vietnam’s Paracel Islands into the 2020 Technical Rules for the Statutory Testing of Seagoing Vessels on Domestic Voyages as a violation of Vietnam’s sovereignty over the Hoang Sa (Paracel) Islands and not beneficial for the maintenance of peace, stability and cooperation in the East Sea," Foreign Ministry spokeswoman Le Thi Thu Hang said Thursday.

The East Sea is referred to internationally as the South China Sea.

China has established what it called the "Hainan-Xisha Navigation Area" in a recently changed document, the South China Morning Post reported July 31. The area is bound by two points on China’s Hainan Island and three in Vietnam’s Hoang Sa Islands, which China calls the Xisha Islands, the paper added.

China also changed its wording, calling the so-called navigation area "coastal" instead of "offshore." It said the new changes would take effect starting August 1.

Hang said: "Vietnam’s consistent stance is that all activities concerning Vietnam’s Paracel Islands without Vietnam’s permission is a violation of Vietnam’s sovereignty and holds no value."

China had seized the Paracel Islands from South Vietnam by force in 1974, and has been illegally occupying it since. The country has also been ramping up its aggressive behavior in the South China Sea since the start of this year while other countries have had to focus on combating the Covid-19 outbreak, including announcing the establishment of the so-called "governed" administrative districts over Vietnam’s Truong Sa (Spratly) and Paracel Islands, sinking Vietnamese fishing vessels and unilaterally ordering a ban on fishing in Vietnamese sea territory.

Vietnam has repeatedly protested these acts and urged China to desist from further provocative, illegal actions.