The arrest of a teenager in a Chinese town triggered pitched battles between hundreds of migrant workers, local people and riot police.
Violence erupted in Shaxi, in the southeastern province of Guangdong, one of China’s major coastal manufacturing areas and continued for two nights.
Authorities in the nearby city of Zhongshan said the fights involved locals and workers predominantly from Sichuan province, which borders Tibet to the west of China.
Hundreds of officers guarded government buildings after the rioting, the latest in a series of clashes in an area where tensions are running high between locals and workers brought in from elsewhere in China.
The BBC reported that around 30 people were injured and two police cars smashed in the rioting in Shaxi, which is just across the water from Hong Kong.
Police said 20 suspects were detained.
In recent years, claims of discrimination and abuse by authorities have triggered strikes, clashes and rioting by migrants, who are on low pay and do not have the same rights as town dwellers.
The latest clashes in Shaxi involved about 300 migrants, who hurled rocks after a fight between a 15-year-old migrant and a student, a government spokeswoman told the Associated Press news agency.
Other reports said the teenager had beaten up a primary school pupil on Monday.
Security personnel intervened and beat the young migrant, infuriating a group of relatives and others migrants who rioted, the Global Times, an English-language Chinese newspaper, reported.
Police are said to have tied up the boy, who suffered facial injuries.
The South China Morning Post reported that authorities sealed off Shaxi on Tuesday and people were told to stay indoors.
For now, the violence has subsided, but riot police were said to still be guarding government buildings yesterday.
Last June, thousands of migrant workers, also largely from Sichuan province, rioted and clashed with police in the Guangdong city of Zengcheng, torching cars and ransacking government buildings, over the treatment of a pregnant street hawker.
Guangdong’s party secretary Wang Yang, who is expected to be elevated to China’s elite politburo standing committee in a leadership transition this year, has acknowledged a need to mitigate simmering social unrest by stressing a more equitable and balanced ‘Happy Guangdong’ campaign.
The number of ‘mass incidents’, as such outbreaks of unrest are known, recorded by the Chinese state grew from 8,700 in 1993 to about 90,000 in 2010, according to several government-backed studies, but some believe the true figures are higher.
The Chinese government has not released official data on such incidents in recent years.