"All activities on the Truong Sa (Spratly) and Hoang Sa (Paracel) Islands must receive Vietnam’s approval. Vietnam asks that China respects its sovereignty and refrain from actions which could escalate tensions, complicate the situation and affect peace and stability in the East Sea and the region, as well as efforts of countries in the negotiation process for the South China Sea Code of Conduct (COC)," Foreign Ministry spokeswoman Le Thi Thu Hang said Thursday.

The East Sea is known internationally as the South China Sea.

Hang was responding to an inquiry on Vietnam's reaction on China setting up two research stations on the Fiery Cross Reef and Subi Reef, which are part of Vietnam's Spratly Islands.

A March 20 Xinhua report said that China has begun operating the Yongshu and Zhubi research stations, on Vietnam's Spratly Islands, which China calls the Nansha Islands. The report said that the two stations operate under the Integrated Research Center for Islands and Reefs of the Chinese Academy of Sciences (CAS) to support geological and ecological research.

"Vietnam has full legal basis and historical evidence to affirm its sovereignty over the Spratly and Paracel Islands in accordance with international law," Hang stressed.

Responding to another query about Taiwan practicing live fire drills around the Itu Aba Island of the Spratly Islands, Hang said it was a serious violation of Vietnam's sovereignty, threatening peace, stability, safety and maritime security on the East Sea, as well as escalating tension and complicating the situation in the area.

"Vietnam vehemently opposes it and requests that Taiwan not practice illegal drills or repeat them in the future," she said.

China claims almost the entire South China Sea, including waters close to Taiwan and Southeast Asian countries Brunei, Indonesia, Malaysia, the Philippines and Vietnam.