US State Department spokeswoman Morgan Ortagus (Photo: C-Span)

Ortagus said the incident is the latest in a string of Chinese actions to assert unlawful maritime claims and disadvantage its Southeast Asian neighbors in the East Sea. She said that, since the global coronavirus outbreak, Beijing has announced new research stations on military bases it has built on Fiery Cross Reef and Subi Reef, and has landed special military aircraft on the Fiery Cross Reef. In July 2016, China’s nine-dashed line was deemed an unlawful maritime claim by a tribunal convened under the 1982 UN Convention on the Law of the Sea, a position shared by the US Government, Ortagus added.

Vietnamese vessel QNg 90617 TS, with eight fishermen on board, was fishing near Phu Lam island on April 2 when a China coast guard ship hit and sank it.

Vietnamese Foreign Ministry spokesperson Le Thi Thu Hang demanded Friday that China investigate the incident, take punitive action against the Chinese vessel, and pay full compensation for the damage caused.

Hang said the actions of the Chinese vessel infringed Vietnam's sovereignty over Hoang Sa or Paracel Islands and endangered the lives and property of Vietnamese fishermen. The sinking of the fishing vessel went against the shared view of senior leaders of the two countries on treating fishermen humanely and against the Vietnam-China Agreement on Basic Principles Guiding the Settlement of Maritime Issues. It also violated the Declaration on the Conduct of Parties in the East Sea and has negatively affected negotiations on a comprehensive Code of Conduct, she added.