"I condemn in the strongest terms China’s sinking of a Vietnamese vessel in the South China Sea. This is a flagrant violation of international law and comes at a time when nations around the world are focused on combating the Covid-19 (pandemic)," Senator Cory Gardner, chairman of the East Asia, Pacific Subcommittee and International Cyber Security Policy of the U.S Senate, said in a statement on April 10.

Foreign Relations Committee Chairman Jim Risch and Senators Bob Menendez and Ed Markey also expressed deep concern about the incident in a joint statement.

"The reports of a Chinese Coast Guard vessel sinking a Vietnamese fishing vessel and China’s other activities on illegally reclaimed features in the South China Sea are deeply concerning," the statement read. These are just the latest examples of China's blatant intimidation of its neighbors to assert its excessive maritime claims.

"The U.S. will work with our allies and partners in the region to uphold a free and open Indo-Pacific and promote peaceful activity in the South China Sea," Risch added.

Fishing vessel QNg 90617 TS with eight Vietnamese fishermen on board was operating in the Phu Lam (Woody) Island area of Vietnam’s Hoang Sa (Paracel) Islands in the East Sea, known internationally as the South China Sea, on April 2 when it was rammed and sunk by a Chinese coast guard vessel. The eight fishermen were taken to the Phu Lam Island.

Three other Vietnamese fishing boats that tried to rescue the Vietnamese fishermen were chased, captured and towed by the Chinese vessel to Phu Lam Island and released the same day. The fishermen on the QNg 90617 TS vessel were safely returned to Vietnam on April 3.

The U.S. State Department and Defense Department have also issued statements expressing concern over the incident, calling it the latest in a series of actions by China to assert illegal maritime claims and disadvantage neighboring South East Asian countries in the South China Sea.

The Philippines has also expressed its concerns and emphasized the need to avoid such incidents because they "undermines the potential of a genuinely deep and trusting regional relationship" between the Association of Southeast Asian Nations (ASEAN) and China.

On the same issue, Vietnam has rejected and protested China sending two diplomatic notes to the U.N., laying claim to Vietnamese territories in the East Sea.

China seized the Paracel Islands from South Vietnam by force in 1974, and has since been occupying them illegally.

In 2014 China brought an oil rig, Haiyang Shiyou 981, and installed it in waters off the Paracel Islands, changing the status quo in the waters. Since then, Chinese ships have chased after and rammed many Vietnamese fishing vessels near the islands in Vietnamese waters.