Mixed reports say several people have been killed and injured in Vietnam as anti-China protesters stormed a huge foreign steel project and set it on fire a day after arson and looting in the south, according to the Associated Press.

The doctor at a hospital in central Ha Tinh province said five Vietnamese workers and 16 other people described as Chinese were killed on Wednesday night in rioting, one of the worst breakdowns in Sino-Vietnamese relations since the neighbors fought a brief border war in 1979, Reuters reported.

"There were about a hundred people sent to the hospital last night. Many were Chinese. More are being sent to the hospital this morning," the doctor at Ha Tinh General Hospital told Reuters by phone.

Foreign Ministry spokesman Le Hai Binh confirmed one death in the clashes, and described media reports and accounts on social networking sites of higher casualties as "groundless," according to Reuters.

China's state news agency Xinhua reported that at least two Chinese nationals had died and more than 100 were hospitalized, Reuters reported.

Vietnamese Prime Minister Nguyen Tan Dung called on police and state and local authorities to restore order and ensure the safety of people and property in the affected areas, according to Reuters. "Appropriate measures should be taken immediately to help businesses stabilize quickly and return to normal production activities," he said in a statement.

The Planning and Investment Ministry blamed the clashes on "extremists" and warned that they could seriously affect the investment environment in Vietnam, Reuters reported. It was not immediately clear if the casualties were among those admitted to the Ha Tinh hospital.

The plant is expected to be Southeast Asia's largest steel making facility when it is completed in 2017, according to Reuters. No details of fire damage or financial losses were immediately available, the company said.

When the Ha Tinh industrial park, planned to be finished in 2020, it will have a port, a 2,100-MW power plant and six furnaces, Vietnamese media say, Reuters reported.

estimated to cost more than $20 billion, is more than half complete.