"The situation in the East Sea is complicated, with unilateral actions including militarization, increasing military exercises, especially the activities of Chinese oil survey ship Haiyang Dizhi 8 and its escorts, which are infringing upon the exclusive economic zone and continental shelf of Vietnam with illegal survey activities," Vietnam’s Deputy Prime Minister and Minister of Foreign Affairs Pham Binh Minh said at the 52nd ASEAN Foreign Ministers' Meeting in Bangkok, Thailand.

Minh stressed that those actions of China seriously violated Vietnam's sovereignty and jurisdiction under the 1982 United Nations Convention on Law of the Sea (UNCLOS).

This is also the next step to escalate disputes and strengthen militarization activities in the sea, he said.

He said these developments undermine trust, increase tensions and directly affect peace, stability, security, safety, freedom of navigation and aviation in the East Sea, known internationally as the South China Sea.

The actions violate the 2002 Declaration on the Conduct of Parties in the South China Sea (DOC) and go against the commitment to maintain a favorable environment for the implementation of the Code of Conduct in the South China Sea (COC) between the ASEAN and China, he said.

The Vietnamese Deputy PM suggested that the ASEAN maintains solidarity and shares a common voice, reaffirms the principles and commitments to peace and stability, calls for restraint, and prevents all  unilateral actions that undermine the process of regional dialogue and cooperation, hinder the legitimate economic activity of coastal countries and the attempts to build an effective, substantive COC.

The 52nd ASEAN Foreign Ministers’ Meeting, Post Ministerial Conferences and Related Meetings are held in Bangkok from July 29 to August 3 with participations of representatives from more than 30 countries, including U.S. Secretary of State Mike Pompeo and Chinese Foreign Minister Wang Yi.

The Chinese survey ship and its escorts have been conducting activities in the southern area of the waters, near Vietnam's Vanguard Bank, since early last month. 

For the second time in a week, the ministry's spokeswoman Le Thi Thu Hang said last Thursday that the act violated Vietnam’s EEZ and continental shelf and demanded that China withdraw its ships from Vietnamese waters.

The case has garnered a lot of international attention.

In a joint communique issued on Wednesday, ASEAN foreign ministers reaffirmed the need to avoid actions that may further complicate the situation in the South China Sea.

The U.S. has made three public statements in the past 10 days, opposing China's "bullying" acts that threaten other nations's sovereignty and undermine peace and security in the region.

One of the statement was a letter by four U.S. senators sent to Secretary of State Mike Pompeo on Monday, asking him to accord high priority to China’s maritime aggression in the South China Sea at the ASEAN Regional Forum to be held Friday in Bangkok.

Experts said China is trying to turn Vietnamese territory into a disputed area to advance its superpower plans, but the actions could erode bilateral and regional trust and affect domestic opinion.

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