The protests have been largely peaceful for much of December after pro-democracy candidates overwhelmingly won district council elections the month before.
Hong Kong's Christmas celebrations were marred by sporadic clashes between police and pro-democracy activists on Wednesday as the city's pro-Beijing leader said the festive season was being "ruined" by demonstrators.
Police used pepper spray and tear gas as activists held small flashmob protests in malls and multiple districts across the city.
In Mong Kok, an area that has seen frequent clashes over the last six months, police fired multiple rounds of tear gas to disperse crowds that were heckling officers.
Pepper spray was also used in at least two malls as police and protesters clashed. Multiple young protesters were detained, some by plainclothes police who had mixed with the crowds, according to live local TV broadcasts.
Wednesday's skirmishes were less sustained than those on Christmas Eve, when battles between democracy activists and riot police swept through a major shopping district for hours.
That evening's unrest was the most serious in what has otherwise been a few weeks of comparative calm for a city upended by more than six months of often-violent protests.
'Reckless and selfish'
Police used tear gas, rubber bullets and pepper spray on Christmas Eve in multiple locations while protesters responded with throwing sporadic petrol bombs, blocking roads and vandalising businesses deemed to be sympathetic to the government.
Hong Kong's pro-Beijing leader Carrie Lam on Wednesday condemned the Christmas Eve protesters on Facebook, describing them as "reckless and selfish rioters".
"Such illegal acts have not only dampened the festive mood but also adversely affected local businesses."
A former British colony with a sizeable Christian population, Christmas has been distinctly muted in Hong Kong this year.
Swathes of the population are seething against Beijing's rule and the semi-autonomous city's administration as they push for greater democratic freedoms and police accountability.
The months of protest have helped tip a financial hub already battered by the US-China trade war into a recession and intensified political polarisation.
The protests were initially sparked by a now-abandoned attempt to allow extraditions to the authoritarian mainland.
They have since morphed into a popular revolt against Beijing's rule, with spiralling fears that the city is losing some of its unique liberties.
Among the demands being made by protesters is an inquiry into the police, amnesty for the more than 6,000 people arrested and the right to elect Hong Kong's leader.
Regulars protests at malls
The city's many malls have become regular protest venues as demonstrators try to cause economic disruption.
Online forums have called for pop-up protests over the Christmas and New Year period targeting shopping districts.
The recent fall-off in violence came after hundreds of hardcore protesters were arrested during a university campus siege – and after the pro-democracy camp won a landslide in local elections – last month.
But both Lam and Beijing have refused any further concessions since that electoral defeat.
Earlier this month, a huge crowd of some 800,000 people marched peacefully.
The same group behind that rally have applied for permission to hold a similar march on New Year's Day.