China sending an oil rig to waters disputed with Vietnam is a move to assert its legal claim and practical hold over contested territory whatever the short-term political and diplomatic costs, analysts say — but could play into Washington’s hands.

Beijing’s controversial move to dispatch the deep-water rig along with a reported 70 vessels triggered clashes in the South China Sea, just after a visit to the region by US President Barack Obama and ahead of this weekend’s Association of Southeast Asian Nations (ASEAN) summit.

It also comes amid heightened tensions between Beijing and Manila, which has asked a United Nations tribunal to rule on China’s claims over most of the sea. Beijing — which prefers to negotiate directly with its smaller, weaker neighbours — has vehemently rejected arbitration.

… The assertiveness of the move against Vietnam suggests that Beijing’s current leadership under President Xi Jinping is “more inclined to adopt a heavy-handed approach” than previous generations, said Li Mingjiang, an expert on East Asian security and an associate professor at the S. Rajaratnam School of International Studies in Singapore.