HANOI, Vietnam -- Vietnamese officials signaled Saturday that further violence over a dispute with China would not be tolerated, declaring that more than 300 people involved in last week's attacks on foreign-owned businesses would be prosecuted.
"They have seriously undermined the country's image, and such action has to be punished," said Gen. Hoang Cong Tu, head of investigations at the ministry of public security.
In the first official accounting of the damage, he told reporters in Hanoi, the capital, that two Chinese workers had died and 140 were injured.
The outburst of looting and arson that left scores of factories flattened was inspired by China's deployment of a deep-sea oil rig in disputed waters about 140 miles off Vietnam's coast.
The action by Vietnam's far bigger northern neighbor and historical foe infuriated the Vietnamese government, which allowed protests to go ahead as a way of showing their displeasure.
But the government was caught by surprise when the protests spread to industrial areas in Ha Tinh province and around Ho Chi Minh City and quickly devolved into violence by Vietnamese workers.
On Saturday, Prime Minister Nguyen Tan Dung sent a text message through the state-run mobile phone company warning citizens not to participate in "illegal protests," and threatening severe consequences if they did. An earlier message from the prime minister was more equivocal, supporting defiance but calling for an end to unrest.
The government, which has tried to project Vietnam as a safe, low-cost foreign investment opportunity, was rattled by the possibility of losing investors, said an American adviser to foreign companies in Vietnam.
But on the main issue vexing China and Vietnam -- the positioning of China's prized oil rig in disputed waters of the South China Sea -- both sides remained entrenched, determined to try to outlast the other.
Although the governments of both countries have gone quiet over what is happening at sea, two people with knowledge of the situation painted a picture Saturday of the continuing standoff.
According to a Vietnamese person with knowledge of the situation, a Chinese armada of navy warships and coast guard vessels is protecting the oil rig, patrolling inside a 10-mile perimeter. A smaller flotilla of Vietnamese warships and coast guard ships continues to try to push past the Chinese boats.
Chinese ships try to stop them, resulting in many incidents of vessels from the two sides ramming each other, said the person who refused to be identified for fear of antagonizing the authoritarian government. The Vietnamese believe that the Chinese are widening the perimeter. When the Vietnamese try to penetrate the Chinese line, the person said, the Chinese come further and further out of the perimeter to stop them, and come closer to the Vietnamese coast.
Four to five Chinese frigates have been dispatched beyond the perimeter, according to a senior U.S. government official who follows the situation from outside Vietnam. About 40 Chinese coast guard vessels are in the immediate vicinity of the rig, and Chinese helicopters fly overhead, the official said, adding that an assortment of 40 other Chinese boats, including fishing vessels, were also in the area.
Vietnam has three to four warships on the way to the area, but so far they are not anywhere near the rig or its perimeter, the official said. About 20 Vietnamese coast guard ships are kept about 12 miles away from the rig by the Chinese, he said.
On the diplomatic front, both China and Vietnam expressed determination to outlast and outwit the other.
"China said Vietnam should withdraw," the president of Vietnam, Truong Tan Sang, said Friday, according to an account on the news portal Vietnamnet. "This is my house. Why do I have to withdraw." He added: "There is no way we compromise."
During a visit to Washington, the chief of the general staff of the Chinese People's Liberation Army, Gen. Fang Fenghui, said Thursday: "China is unwaveringly committed to carrying out drilling activities in its own territory, lands and seas."
"We will not brook any meddling or sabotage from outside," Gen. Fang added.
The contest between Vietnam and China over the oil rig has caused alarm in Southeast Asia because of the boldness of China's move, one that is clearly designed to solidify its grasp on the South China Sea. China claims about 80 percent of those waters.
Even within China, the dispatch of the oil rig was seen as a tough signal, and analysts suggested President Xi Jinping may have given the final go-ahead because the decision involved a state-owned company moving an extremely expensive piece of equipment and the deployment of considerable naval assets.