China has evacuated more than 3,000 of its nationals from Vietnam, state media reported Sunday, after a wave of anti-China unrest following Beijing's deployment of an oil rig in contested waters.
The announcement came after Vietnamese civil society groups on Saturday called for fresh demonstrations against China following riots earlier in the week which left two Chinese workers dead and more than 100 injured.
But Vietnamese authorities, which have occasionally allowed protests to vent anger at the country's giant neighbour, warned they would "resolutely" prevent any further outbursts.
More than 3,000 Chinese nationals had been evacuated from Vietnam as of Saturday afternoon, China's official Xinhua news agency reported early Sunday.
"They returned to China with the assistance of (the) Chinese Embassy to Vietnam," it said, citing China's Foreign Ministry.
The Chinese government is also arranging for a chartered plane and vessel to evacuate the staff of China 19th Metallurgical Corporation, a contractor of one of the plants badly hit by the recent violence, Xinhua added.
In a later update the agency reported: "Sixteen critically injured Chinese nationals were evacuated from Vietnam early Sunday morning aboard a chartered medical flight arranged by (the) Chinese government." It did not elaborate which company they are working for.
Beijing on Saturday advised its nationals against travelling to Vietnam, which has over the past week seen its worst anti-China unrest in decades.
China's positioning of an oil rig in waters also claimed by Vietnam in the South China Sea has ignited long-simmering enmity between the two communist neighbours, which have fought territorial skirmishes in past decades.
Worker demonstrations spread to 22 of Vietnam's 63 provinces in the last week, according to the Vietnamese government, with enraged mobs torching foreign-owned factories.
"Recently, there was an explosion of violence in South Vietnam targeting foreign companies, provoking injuries and death of Chinese citizens and damaging companies' properties," China's Foreign Ministry said in a statement in Chinese on its website Saturday.
"The Foreign Ministry advises Chinese nationals temporarily not to travel to Vietnam. (It also advises) Chinese citizens and structures in Vietnam to increase their risk-awareness, to strengthen their security prevention measures, and to avoid leaving (their premises)."
Hong Kong also updated its travel advisory Saturday, warning its residents to avoid "non-essential travel" to Vietnam.
Earlier Saturday, Xinhua reported that security chief Guo Shengkun had spoken to his Vietnamese counterpart and urged the authorities there to quell the violence. Xinhua also said commerce minister Gao Hucheng had called on officials to "bring relevant issues under control".
- Call for fresh, peaceful protests -
An alliance of 20 vocal Vietnamese NGOs has called for fresh protests in the capital Hanoi, the southern economic hub of Ho Chi Minh City, and other areas against China's "aggressive actions" in the South China Sea.
However, it urged participants to remain peaceful following the chaos Tuesday and Wednesday.
"Those violent actions created a bad image for patriotic demonstrations and the people of Vietnam; therefore, they must be stopped," said a statement issued on social media late Friday.
The alliance comprises largely of anti-government organisations and is believed to have played a role in stirring the recent protests.
In a text message sent by the government to Vietnamese mobile phone users Saturday, Prime Minister Nguyen Tan Dung said authorities across the country had been ordered to "implement measures to resolutely prevent illegal demonstrations that could cause social and security disorder".
China's deployment of the giant rig is viewed in Hanoi as a provocative assertion of Beijing's hotly-disputed claims in the South China Sea, and has been criticised by Washington as exacerbating territorial tensions.
There have been repeated skirmishes near the controversial rig in recent days between Chinese and Vietnamese vessels, including collisions and the use of water cannon.
The violent attacks on Chinese personnel at foreign-invested factories in Vietnam have further aggravated the situation, with China accusing Hanoi of a role in the unrest.
Beijing, which has refused to budge on the oil rig, has said two Chinese nationals were killed and more than 100 injured over the past week.
The attacks on foreign enterprises -- which included Chinese, Taiwanese and Korean businesses -- appear to have spooked Vietnamese authorities, which depends heavily on foreign investment for economic growth.
But, while condemning China's maritime actions, the government has warned against further protests and pledged foreign investments would be protected.
The oil-rig confrontation is the latest to spark alarm among China's Southeast Asian neighbours, which complain of increasing maritime intimidation by Beijing.
China claims nearly all of the South China Sea, which is believed to hold significant offshore energy reserves.