Hong Kong's Carrie Lam bans protesters from wearing face masks in dramatic move to stop anti-government demonstrations

Hong Kong leader Carrie Lam has banned protesters wearing face masks in a dramatic move to quell anti-government protests.

The legislation, called the Emergency Regulations Ordinance, is a colonial-era emergency power that has not been more than for over 50 years.

It marks a dramatic toughening in her response to the most serious crisis to wrack Hong Kong since the territory reverted from British to Chinese rule in 1997.

Speaking at a news conference, Ms Lam said a ban on face masks would take effect from Saturday under the emergency laws that allow authorities to "make any regulations whatsoever" in the public interest.

She added: "We must stop the violence."

The mask ban applies to people at "illegal" gatherings who use violence, she said.

It exempts those who wear masks for "legitimate need." Ms Lam said she would go to the legislature later to get legal backing for the rule.

Thousands of masked protesters chanted slogans calling for greater democracy as they marched in the city's business district before Lam spoke.

They chanted "I want to wear face masks" and "Wearing mask is not a crime" as many cars, stuck in traffic due to the march, honked in support.

"Will they arrest 100,000 people on the street? The government is trying to intimidate us but at this moment, I don't think the people will be scared," one protester, who gave his surname as Lui, told an online live broadcast.

At the nearby Causeway Bay shopping area, a huge crowd also occupied streets to protest the mask ban. Smaller rallies were also held in several other areas.

Analysts warned the use of the Emergency Ordinance for the first time in over half a decade set a dangerous precedent.

The law, a relic of British rule enacted in 1922 to quell a seamens strike and last used to crush riots in 1967, gives broad powers to the city's chief executive to implement regulations in an emergency.

The ban followed widespread violence in the city on Tuesday that marred China's National Day and included a police officer shooting a protester, the first victim of gunfire since the protests started in June. The wounded teenager was charged with attacking police and rioting.

Hong Kong's protests started in June, sparked by proposals to extradite suspected criminals to mainland China.

Critics feared this could undermine the city's judicial independence and endanger dissidents.