A China national was killed by mobs and more than 50 workers were injured at a mill in Ha Tinh province in central Vietnam, 155 miles south of Hanoi.
The factory is operated by Formosa Plastics Group, one of the biggest foreign investors in Vietnam.
Around 6,000 workers initially held peaceful protests against Chinese oil drilling in Vietnam’s territorial waters on Tuesday in the Vietnam-Singapore Industrial Park 1 (VSIP 1) in Thuan An District, Thanh Nien News reported.
But the demonstrations grew to about 20,000 and violence erupted.
More than 700 people were arrested for inciting and participating in rampages against businesses believed to be Chinese-owned around Ho Chi Minh City on Tuesday and Wednesday.
Police of Binh Duong Province arrested about 600 people for rioting and looting, major general Vo Thanh Duc, the local police chief told Thanh Nien.
In adjacent Dong Nai Province, police said they have arrested about 100 people.
More than 460 local companies have been wrecked and vandalized.
Many warehouses have been burned to the ground.
Some China and Hong Kong-based businesses have withdrawn their personnel from Vietnam over safety concerns.