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For months, Hong Kong's pro-democracy protesters have taken to the streets, their identities concealed behind masks.

But on Friday - in the face of increasingly violent clashes between hard-line protesters and police - the Chinese territory's government enacted a ban on face masks with the help of a colonial-era law which hadn't been used in decades.

The ban came into effect at midnight Hong Kong time (16:00 GMT) - potentially changing the face of the protests.

Because these masks weren't just a way for the movement to hide their identities from police, employers and parents, but also a layer of protection against the tear gas fired into the demonstrating crowds.

But protesters were not going down without a fight: legal challenges have been launched, with thousands of masked activists taking to the city's streets to voice their anger.

Image copyright EPA Image caption Protesters wasted no time demanding the ban was revoked, demonstrating against it before it was officially announced

Image copyright Reuters Image caption Thousands of people donned masks during their lunch breaks, before many returned to their offices

Image copyright Reuters Image caption But they rejoined the protests after chief executive Carrie Lam announced the ban would come into effect at midnight

Image copyright Reuters Image caption Some people have taken to wearing gas masks in recent weeks, due to the tear gas

Image copyright AFP Image caption There was mounting anger at Ms Lam, who critics accuse of being a puppet of the Beijing government

Image copyright AFP Image caption The comedic tone of some masks belied the anger felt. Opposition figures warned it could be the first of more "draconian" steps

Image copyright AFP Image caption As night fell, the anger appeared to intensify, with buildings and train stations vandalised

Image copyright Reuters Image caption Beijing has welcomed the ban, saying it is neccesary to bring the protests to an end

Image copyright AFP Image caption However, few know how the police will actually enforce the rule should Hong Kong's protesters choose to ignore it

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