Yi Xianliang, deputy director-general of ocean affairs at the Chinese Foreign Ministry, challenged claims from Vietnam that a drilling rig was operating in Vietnamese waters.
PetroVietnam, the country's state-owned energy company, said last weekend drilling rig HD-981, deployed by the China National Offshore Oil Corp. about 120 miles off the coast of Vietnam, was encroaching on its sovereignty. The Vietnamese government said it would take "all the proper and necessary measures" to protect its interests.
Yi said Thursday said the Chinese government, however, was "deeply surprised" by Vietnam's reaction. The rig, he said, was operating completely within Chinese territorial waters.
U.S. State Department spokeswoman Jen Psaki said during her regular press briefing Thursday the Chinese side was taking "provocative" actions over the dispute. It's not for the United States to determine territorial claims, though "dangerous conduct [by China] ... is concerning," she said.
China and Vietnam have made competing claims of aggression in the ongoing row.
China is at odds with many of its territorial neighbors over claims to the South China Sea.
"We believe that all sides should operate in a way that reduces tensions," the State Department spokeswoman said.