US National Security Adviser O'Brien criticized China for "threatening" countries that exploit resources in the South China Sea when speaking in Bangkok.

"Beijing has used a threat measure to try to prevent ASEAN countries from exploiting offshore resources, hindering access to oil reserves worth US $ 2,500 billion," US National Security Advisor Robert O'Brien today speaking at the ASEAN - US Summit in Bangkok, Thailand.

According to O'Brien, the region will not accept a "new feudal era", when a large country can rule over other countries with the argument that "the truth belongs to the strong".

He also read President Donald Trump's message, expressing his desire for ASEAN leaders to attend the "special summit in the US in early 2020".

President Trump has been absent from the ASEAN-US Summit for the past two years. He sent Vice President Mike Pence to the event last year, while Commerce Secretary Wilbur Ross was the top US official to attend this year's conference.

China makes illegal claims in the South China Sea, and repeatedly dispatches ships to invade the waters of the countries in the region. China's Hai Duong 8 Survey Group has engaged in violations of Vietnam's exclusive economic zone and continental shelf in the southern part of the South China Sea since July and left only on October 24.

Vietnam has repeatedly objected to China's actions, asserting that the acts that hinder oil and gas activities in Vietnam's waters are violations of international law and violations of the United Nations Convention on the Law of the Sea ( UNCLOS) 1982.