The embassy posted a notice on its website referring to the protests as "illegal gatherings" that had included some "anti-China content".
Apart from Binh Thuan, large crowds of protesters also gathered in Ho Chi Minh City, Da Nang, Hanoi and other places to protest the draft law on SEZs. It added, "The Chinese embassy in Vietnam is closely monitoring the trend".
The Ministry of Public Security is investigating what led to protesters hurling bricks and Molotov cocktails at police and damaging some government buildings in Binh Thuan province, where anti-Chinese sentiment boiled over.
Though the authorities often tolerate protests, rallies against China's perceived aggression and infringements upon Vietnamese sovereignty are a challenge for the government, which is keen to avoid angering a neighbor with growing military, political and economic clout.
Vietnam's National Assembly decided on Monday to delay a vote on a draft bill on special economic zones aimed at luring foreign investors.More news: Foxconn scrutinizing harsh working conditions at factory for Amazon products
Vietnam said the groups behind Sunday's protests against proposed laws demonstrators view as curbing Internet freedom and favoring Chinese investors were trying to damage the country's image, after the rare display of public activism reportedly turned violent.
The demonstrators carried anti-China banners, including one that said "No leasing land to China even for one day", on a busy street near Hanoi's Hoan Kiem Lake.
Nhieu also said that dozens of police officers sustained injuries but there were no deaths, shutting down rumours that had spread on social media.
One of the most controversial provisions of the draft law was to allow foreigners to lease land in the three special economic zones for up to 99 years.
The National Assembly was due to pass the legislation for the economic zones later this week but made a decision to delay the vote until its next meeting in October.More news: G7 allies confront Trump with trade numbers in tense G7 summit
The government has said the bill aims to boost development in three provinces in northern, central and southern Vietnam and provide "room for institutional experiments".
Authorities in Vietnam's south central province of Binh Thuan have strongly condemned a protest that broke out in the province on Sunday as "causing very serious consequences".
Vietnam is among several countries in the region that have claims in the South China Sea, through which an estimated $5 trillion in trade passes each year.
The protests come at a time of rising tensions over the disputed South China Sea, almost all of which is claimed by China.
The bill was deferred by the National Assembly on Monday at the government's behest.More news: Real Madrid Reportedly to Rival Manchester United for Sergej Milinkovic-Savic
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