Speaking at a press conference, spokeswoman Jen Psaki further said that the US is closely monitoring the move, adding that given the recent history of tensions in the sea, China 's decision to operate its oil rig in the waters is "provocative and unhelpful to the maintenance of peace and stability in the region".

"These events point to the need for claimants to clarify their claims in accordance with international law, and reach an agreement... about what types of activities should be permissible within disputed areas," she stressed.

VNN/VNS