On Thursday, Vietnam criticized China over the location of an oil rig, calling on Beijing to abandon plans to drill in contested waters, in the latest sign of regional unease.
The $1 billion oil-extraction structure, which led to a diplomatic standoff between the two countries in 2014, was moved by Beijing to the Gulf of Tonkin in the South China Sea, despite Vietnamese claims that the countries still needed to "execute delineation discussions."
In a statement, Vietnam’s Foreign Ministry spokesman Le Hai Binh said: "Vietnam resolutely opposes and demands that China cancel its plan to drill and calls on China to immediately remove the Hai Duong 981 oil rig out of this area."
In the statement, Binh also said that China must take "no further unilateral actions that further complicate the situation, and make practical contributions to peace and stability."
The incident comes two years after China parked the oil rig for 10 weeks in waters Vietnam claimed were its exclusive economic zone, which severely strained tensions between the two countries that had previously been allies.
Since the incident two years ago, Vietnam has worked to normalize relations with Washington, further complicating China’s diplomatic reputation throughout the South China Sea region.
Binh also criticized China’s decision to build and operate a lighthouse along the Spratly archipelago, claiming the move by China violated Vietnam’s sovereignty and calling it "illegal and worthless."
Amid rising regional tensions, China continues to claim most of the territory in the resource-rich South China Sea, despite rival claims by Brunei, Malaysia, the Philippines, Taiwan and Vietnam.