A senior Beijing official blamed "radical separatists" for the series of clashes in Hong Kong last week between food vendors and police that have been dubbed the "Fishball Revolution."
Beijing's top representative Zheng Xiaoming told reporters that the violence left "dozens of police officers hurt" and "showed elements of 'terror.'"
"We strongly condemn those radical separatists who have become increasingly violent, even [carrying out] activities that showed terror tendencies," the director of China's Liaison Office in Hong Kong said, according to AFP.
The city's Lunar New Year festivities took a turn for the worst around 10pm last Monday, when police donned riot gear in a bid to clear hawkers selling their wares along a main thoroughfare. The crowd lobbed glass bottles and ceramic pots at law enforcement, who responded with pepper spray. Called the "Fishball Revolution" after the popular Hong Kong street food staple, tensions have risen around city authorities' efforts to clamp down on street food vendors.
The unrest provided a window of opportunity for groups like Hong Kong Indigenous, a radical localist political group, to march and rally supporters. Hong Kong leader Leung Chun-ying said that most of the protesters were "unemployed and did not reflect mainstream views."
"The majority of them are jobless. Quite many of them belong to radical political groups. Their political demands… cannot reflect the majority of society," he said.
The violence has compounded a sense of unease since an "Occupy Central" pro-democracy movement in late 2014 that saw thousands of protesters block major roads, including in Mong Kok, to demand Beijing's Communist leaders allow full democracy in the city.
More than 100 people were injured, 65 were arrested, and some 30 have been charged with rioting. Of those arrested, 22-year-old student activist Derek Lam Shun-hin, was "detained and arrested by the police half an hour before departure at the Hong Kong airport" on Wednesday, according to student activist group Scholarism's Facebook page.
Thirty-seven people were charged on Thursday with participating in a "riot." Three more appeared in court on Friday, including a 15-year-old.
Outside the courthouse, several supporters of the defendants scuffled with a small group of men who held up banners denouncing Monday's violence.
Hong Kong's Justice Secretary Rimsky Yuen said the riot charge, rarely used in Hong Kong, was leveled because of what he called the seriousness of the incident. He also said it was a "big test" of the rule of law in the financial hub.
"I think everyone would agree that unlawful violence would not be the appropriate way to express one's political demands and one's political motives," Yuen told reporters.
He said authorities would consider pressing more charges in coming weeks after examining more evidence.
At least one of those charged in connection with the riot belongs to a group called Hong Kong Indigenous, one of a cluster of outspoken groups calling for greater Hong Kong autonomy and even independence from China, the group said.
China's Foreign Ministry said the riot was "plotted mainly by a local radical separatist organization".
"The violence quickly subsided as the Hong Kong police took effective measures in a professional manner with restraint and in accordance with the law," the statement said.