Hong Kong — A protester who was shot by a Hong Kong police officer during mass demonstrations on Tuesday has been arrested and charged with assaulting an officer and could face further charges for rioting. CBS News correspondent Ramy Inocencio reported Wednesday that the pro-democracy activist was in stable but critical condition after being shot in the chest at point-blank range.

Hong Kong Police Commissioner Stephen Lo defended the officer who pulled the trigger, calling his actions "reasonable and lawful."

Inocencio said it was the first known instance of a protester being hit with live ammunition during the protests, marking a dangerous escalation in the violence that has divided the semi-autonomous Chinese territory since June.

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Earlier Wednesday, classmates of the 18-year-old student protester staged a demonstration outside his school.

The crackdown on the protests Tuesday came as China celebrated the 70th anniversary of the founding of its ruling Communist Party with a massive parade across Tiananmen Square in Beijing, showing off its most advanced missiles to date — including one with the capability to hit anywhere in the continental United States.

For a time on Tuesday, Inocencio said Hong Kong resembled a war zone as the pops of live ammunition echoed across the city's streets and black smoke billowed from fires set by protesters in various districts.

It was during a brawl between one group of demonstrators and police that an officer shot the young protester in the chest. The student was left bleeding on the ground and screaming in Cantonese, "My chest is in pain. I want to go to the hospital."

The incident has ratcheted up already-high tensions between protesters, police and the government since the mass demonstrations began 17 weeks ago.

The movement was sparked by a controversial extradition bill seen as an attempt by Beijing to erode the freedoms granted to Hong Kong when the region was handed back to China in 1997 after decades of British rule.

The protesters had initially only demanded that the extradition bill be withdrawn, but a harsh reaction by authorities to the rallies led the pro-democracy movement to issue a five-point list of demands, including the right to directly elect their future leaders and for Hong Kong's current Beijing-appointed Chief Executive Carrie Lam to step down.

"We are not fearful and we will continue to fight for our rights and I think it sends a very important message for the world to listen that Hong Kong people will continue to fight," Lee Cheuk-yan, a former Hong Kong legislator who has joined the protest movement, told CBS News.

The protests have plunged Hong Kong into chaos. The government has responded by labeling protesters "rioters," which automatically carries a longer prison term — a tactic pro-democracy activists warn is just one step closer to declaring martial law.