Calum MacLeod

USA TODAY

BEIJING — Vietnam's Prime Minister texted millions of citizens late Thursday encouraging them to defend the nation's sovereignty in a dispute with China over an oil rig that has left at least two Chinese workers dead and injured a 100 more.

Nguyen Tan Dung warned against letting "bad elements" engage in violence, but did not directly condemn anti-China riots that took place in Vietnam this week. Vietnamese authorities have arrested over 600 suspects, but more anti-China protests are planned in Vietnam this weekend.

Chinese Foreign Ministry spokeswoman Hua Chunying accused Hanoi Thursday of "indulgence and connivance" toward the mobs that attacked many Chinese factories in Vietnam on Tuesday and Wednesday. Hundreds of Chinese workers have fled overland to Cambodia or rushed to airports for over-booked flights back to China.

While China and Vietnam are both one-party, nominally socialist states, tensions have long troubled their relationship.

Vietnamese remain highly suspicious of their giant neighbor, with whom they fought a border war in 1979. An earlier clash, in 1974, gave China de facto control of the Paracel Islands, where China towed a deep-sea oil drilling rig on May 1.

That move sparked the latest troubles, and highlighted Beijing's increasingly assertive approach to its territorial claims that cover almost the entire South China Sea, one of the world's busiest waterways and potentially rich in oil and gas. China now has several maritime disputes simmering with countries nervous of Beijing's growing economic and military power.

Vietnam says 80 Chinese ships are protecting the oil rig, deployed some 120 miles from Vietnam's coast and therefore well within Vietnam's 200-mile exclusive economic zone, as defined by the U.N. Convention on the Law of the Sea. Both sides have accused the other of "provocations" as boats have collided, and Chinese ships have used water cannons, according to Vietnamese media.

Vice President Joe Biden and other top U.S. officials told a top Chinese general visiting the U.S. this week that Beijing's behavior in the dispute was "dangerous and provocative" and must stop, a senior U.S. official told Reuters news service. Beijing thinks Washington should mind its own business, and shows no intention of withdrawing the rig.

Following anti-China protests last weekend, further protests are planned across Vietnam this Sunday, said Le Dang Doanh, a Vietnamese economist and former government adviser in Hanoi. "As long as the oil rig is not withdrawn from Vietnam's continental shelf, the Vietnamese people will continue to demonstrate, and their emotions will continue to be angry and sensitive," he said.

Doanh called the riots an "unfortunate and isolated event", and expected Sunday's protests would be peaceful and heavily-policed. "Vietnamese people want to keep peace, but it would be a miscalculation to take that as weakness," he said. "I hope that no more will the international community allow a newly emerging imperial power, or newly colonialist power, to intimidate its neighbors," said Doanh, who looks to the U.S. to strengthen its military presence in what Vietnam calls the East Sea.

On his Asia tour last month, President Obama tried to convince allies of the sincerity of the U.S. "pivot" or "rebalancing" policy to the Asia-Pacific, after years focused on Afghanistan and the Middle East.