Vietnam has accused China of dragging a giant oil drill rig back into disputed waters off its coast – a move that threatens to reignite tensions at a time of acute political sensitivity in Hanoi.
Relations with China are a hotly debated issue as rival factions in the Communist Party fight it out over the appointment of new top leaders for party and state.
The Vietnamese foreign ministry said the billion dollar rig, Haiyang Shiyou 981, had been moved to an area where the continental shelves of the two countries meet, between China’s Hainan Island and central Vietnam.
“This is an overlapping area that has not been demarcated. Vietnam demands that China not conduct drilling and withdraw the oil rig from the area,” the foreign ministry spokesman, Le Hai Binh, said in a statement.
The movement of the rig into adjacent waters in 2014 led to a dangerous confrontation at sea and sparked violent anti-China riots across Vietnam.
The rig’s reappearance, on the eve of Vietnam’s long awaited 12th Party Congress and hotly contested leadership battle, will raise suspicions that China is attempting to influence the outcome.
Beijing’s recent despatch of civilian aircraft to land on its newly reclaimed islands in the disputed Spratly Islands also provoked a strong response from Vietnam, which described the flights as a violation of Vietnamese sovereignty.
The long time favourite to emerge as the new party leader, seen as the top post in Vietnam’s tripartite system, is the two-term prime minister, Nguyen Tan Dung. He stood up most strongly to China during the confrontation in 2014 and is seen as favouring warmer ties with Washington.
He is, however, facing a strong challenge from the incumbent, Nguyen Phu Trong, who has traditionally been seen as a conservative with close links to Beijing.
Unconfirmed reports say the outgoing politburo has recommended that Mr Trong stay in his post for now, in what would be a startling challenge to Mr Dung’s ambitions.
The final decision remains with the congress, whose delegates are just beginning to gather in Hanoi.
Analysts caution that since 2014, China has made moves to repair its relations with Mr Dung, while Mr Trong showed that he too could be flexible with his historic visit to Washington in July last year.
China’s true intentions remain as opaque as the manoeuvrings inside the party leadership in Hanoi.
If China does intend to keep the rig inside the disputed waters, tensions can be expected to rise once again.
It eventually removed the rig after a ten-week standoff in 2014, by which time relations with Hanoi had suffered their biggest setback for years.
Vietnam has since sought to improve ties with Washington, Japan and the European Union, with whom it has since signed free trade agreements.
Vietnam has been seeking to ease its heavy economic dependence on China and signal to Beijing that it does have other options.
Few analysts expect a dramatic change of policy in the immediate future, although Vietnam’s approach to China will clearly be heavily influenced by the outcome of the leadership battle currently being played out in Hanoi.