Beijing's top representative in Hong Kong has blamed radical separatists for riots that erupted in the Chinese-ruled city almost a week ago.
The city experienced the worst violence since pro-democracy protests paralysed parts of the Asian financial centre in 2014.
More than 60 people have been arrested in connection with the violence, during which protesters hurled bricks at police and set fire to rubbish bins in Mong Kok, a tough, working-class neighbourhood just across the harbour from the city's financial district.
Thirty-seven people were charged on Thursday.
The riots erupted when authorities tried to remove illegal street stalls set up for Lunar New Year celebrations.
The actions of the "radical separatists" were "leaning towards terrorism", the South China Morning Post daily quoted Zhang Xiaoming, the head of Beijing's Liaison Office in Hong Kong, as saying.
"We will not let this very small number of radical separatists destroy the most precious rule of law in Hong Kong," he told a spring festival in Hong Kong.
Police fired two warning shots into the air during the violence, almost unheard of in the former British colony that reverted to Chinese rule in 1997 and is considered one of Asia's safest cities.
More than 130 people were wounded in the clashes.
At least one of those charged in connection with the trouble 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.