Police dogs were seen at protest clearance operations without any protective gear while riot officers wearing respirator masks fired tear gas.
The movement's supporters say exposing dogs to tear gas amounts to animal cruelty and threatens their lives.
The 30,000-strong force said on its Facebook page that "no police dog has passed away or felt unwell as a result of handling protests since June."
Protesters said they will also march Sunday in support of the former British colony's ethnic and religious minorities, in a show of unity after police used a water cannon to spray a mosque and bystanders the previous weekend.
The route of the rally will include the mosque and nearby churches and temples.
Hong Kong protesters have taken to the streets for more than four months.
The movement was initially sparked by an unpopular extradition bill that many residents worried would put them at risk of being sent into China's Communist Party-controlled judicial system.
The government formally withdrew the bill last week, but the movement has snowballed to include demands for political reform and police accountability.
At a rally on Saturday night organized by medical workers to oppose what they called "violent repression" by police in response to protesters, some protesters jeered and cursed several officers observing from a footbridge.
Earlier Saturday, the Hong Kong government won a temporary court order banning anyone from posting personal details or photos of police officers online.
The order prohibits unlawfully "publishing, communicating or disclosing" officers' details including their Facebook and Instagram account IDs or photos of officers or their family members.
This month, an 18-year-old was charged with intentional wounding for a slashing attack on a riot officer.
Despite repeated government appeals for people not to side with mobs involved in vandalism, throwing gasoline bombs and other violence, the protest movement is still rousing determined support from more moderate demonstrators.
They're broadly worried about the future and freedoms of the city that reverted to Chinese rule in 1997, with promises from Beijing that it would largely be its own boss, its way of life unchanged.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)
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