At least two Chinese workers were killed and more than 100 injured in escalating anti-China riots and protests in Vietnam.
Hundreds of Chinese factories operating in the country were either destroyed by rioters or forced to close.
Beijing said the rioting and protests had been staged "with the indulgence and connivance" of the Vietnamese government.
Foreign Minister Wang Yi "strongly condemned" the violence, and lodged a protest against the Vietnamese government.
In a telephone call to Vietnamese Foreign Minister Pham Binh Minh on Thursday night, Wang said Hanoi bore unshirkable responsibility for the riots against Chinese businesses in Vietnam.
He urged Vietnam to take effective measures to end the violence, severely punish the criminals and compensate the Chinese enterprises and individuals for their losses.
Many of the factories were operated by businesses from the Chinese mainland, Taiwan and Singapore.
Xinhua reported that at least two Chinese workers were confirmed dead, but there were fears that many more Chinese nationals may have been killed.
A doctor at a hospital in the central Vietnamese province of Ha Tinh told Reuters that 16 Chinese and five Vietnamese workers were killed on Wednesday.
A high-ranking official at China 19th Metallurgical Corp said: "By our count, the hospital has received 75 Chinese nationals. Dozens of Chinese were sent to another provincial hospital."
His company was one of the worst-hit on Wednesday among the Chinese enterprises operating in Vietnam.
A steel mill in Ha Tinh province owned by Formosa Plastics from Taiwan was destroyed.
Local official Dang Quoc Khanh said one male Chinese worker was killed in the chaos and at least 149 people injured, Vietnam Television reported, adding that police had arrested 76 people.
Foreign Ministry spokeswoman Hua Chunying said at a news briefing in Beijing on Thursday that the violence targeting Chinese had "a direct link with the Vietnamese government's indulgence and connivance in recent days toward domestic anti-China forces and lawbreakers".