Vietnam this week said it was frustrated with China's decision to send a drilling rig into contested waters. Vietnamese Deputy Prime Minister Pham Binh Minh said the move was a direct violation of his country's sovereignty.
"Vietnam will take all the proper and necessary measures to protect its legitimate rights and interests," he said.
Beijing said Monday the rig sent by China National Offshore Oil Corp. was operating in a maritime area controlled by the Chinese government.
U.S. State Department spokeswoman Jen Psaki said during her regular press briefing Tuesday the decision from China was "provocative and unhelpful to the maintenance of peace and stability in the region."
Territory in the South China Sea has been a source of dispute between China and many of its neighbors in the Asia-Pacific region.
China's official Xinhua News Agency reported Wednesday a fishing boat in the South China Sea was intercepted by armed men, who took 11 Chinese fisherman hostage.