HONG KONG — Among the Hong Kong guests invited to a lavish military parade in Beijing celebrating China’s National Day were the usual suited tycoons and pro-China politicians — and then there was a bald man who has become familiar on both sides of the border: Sgt. Lau Chak-Kei of the Hong Kong police.

Lau, 46, is despised by many in Hong Kong for pointing a shotgun loaded with beanbag rounds at protesters outside a police station on July 30, in an early and pivotal moment of an escalating use of force that shocked the global financial hub. He was berated by Hong Kong residents, received prank calls to his home and had his picture plastered on “Lennon Walls” across the city. 

The incident, however, gave Lau hero status in mainland China as a defender of law and order in the face of foreign-backed troublemakers: He was invited to prime-time television shows, flooded with messages of support on Chinese social media and given red-carpet treatment when he arrived in Beijing for the parade. He was given preferential access to the Great Wall of China along with nine other officers and hiked it with the Chinese flag held firmly in his right hand. The state press was there to cover it.

The contrasting reactions to Lau after the incident underscore a new reality for the Hong Kong Police Force. It is seen here increasingly as an occupying force, an arm of Beijing tasked with crushing the city’s freedoms. In Beijing, the Hong Kong police are seen as saviors and protectors of Chinese unity. 

For many protesters, China’s warnings of military intervention are immaterial, as are fears of another Tiananmen-style crackdown. The oppressors are already here, in this view, and they are the Hong Kong police. 

The situation appears likely to worsen after officers fired live rounds at protesters Tuesday. Protests broke out in several areas of the city Wednesday, the first in central Hong Kong during the lunch hour, apparently involving office workers in the city’s financial district. At night, demonstrators gathered in at least three areas, calling for the police force to be disbanded. In Tsuen Wan, where a police officer shot a teenager a day earlier, police fired tear gas at protesters who had occupied roads and thrown gasoline bombs. In one area, protesters invaded a subway station and vandalized it.

Some analysts now warn that this could be the start of years of unrest, and they worry it could deteriorate into the kind of protracted violence and radicalism that roiled places such as Northern Ireland in decades past.

Police actions in recent months have “profoundly damaged their standing in Hong Kong society while at the same time being utterly inefficient in the goal of actually curbing the protests,” said Mike Chinoy, who covered the conflict in Northern Ireland as a journalist and is now a Hong Kong-based nonresident senior fellow at the University of Southern California’s U.S.-China Institute.

A lack of political leadership, as well as mixed signals early on from police brass, meant that the “Hong Kong police were being asked to solve on the street what is essentially a political problem,” Chinoy added. 

While Lau was taking in the military firepower on display in Beijing — with a temporary tattoo of the Chinese flag on his hand — Hong Kong was descending into a new level of chaos. Despite warnings of violence and threats of arrest, protesters — peaceful ones and those looking for a fight — gathered in half a dozen locations across the city. 

With placards and chants, they rejected the notion that their semiautonomous city is anything like mainland China, pushed back against Beijing’s control and demanded free, direct elections for city leaders. Protests were sparked in June by a bill to allow extraditions to mainland China, but they have swelled into an all-out rebuke of Hong Kong’s political system, in which leaders are handpicked by and answerable to Beijing. 

Demonstrators are pushing five demands, including an independent investigation of the police, but the government has responded only to the first demand, the full withdrawal of the extradition bill. 

A new escalation came when a riot officer shot an 18-year-old at close range in the upper body, apparently after the protester hit him with a rod, according to police and a video of the melee. After he was shot and as he was lying wounded on the ground, surrounded by officers, a separate video showed another protester flinging a molotov cocktail at the group of police officers. 

Upon hearing about the shooting, prominent Hong Kong activist Joshua Wong said in a tweet: “The true lesson Beijing learnt from 30yrs ago is, perhaps, to ask someone else to undertake the butcher role,” a reference to the use of Chinese army troops to crush the 1989 Tiananmen Square pro-democracy sit-in.

According to police, 1,400 rounds of tear gas were fired Tuesday, compared with just 150 canisters used in the June 12 protest. In addition, police fired about 900 rubber bullets and six live rounds. At least 269 people were arrested, raising the total detained to more than 2,000.

The Hong Kong Police Force was quick to defend the officer who shot the teenage protester, saying he feared for his life.

“Our National Day is supposed to be a day to celebrate and be happy, but unfortunately some rioters choose to do all these sorts of criminal damages, arson, wounding, assaulting police officers and various behaviors, which are more or less equivalent to a riot offense,” Stephen Lo, Hong Kong’s police commissioner, said in a news conference late Tuesday. 

Yet, it was the gunshot wound, rather than the arson, gasoline bombs and vandalism, that has left many here stunned and deeply worried about the future of a city where police shootings are rare and the force for decades has been respected and honored.

Francis Lee, director of the School of Journalism and Communication at the Chinese University of Hong Kong, said that despite “heightened levels of violence,” the public generally has remained sympathetic to the protesters because of perceptions of government inaction, unresponsiveness and “repeated police misconduct.” 

“In this situation, many citizens find it hard to blame the protesters even if they might not feel entirely comfortable with some of the most violent tactics, such as the use of petrol bombs,” Lee said. 

Numerous accounts from the demonstrations describe how residents often give shelter to protesters fleeing police.

A public opinion survey from Lee’s university shows the share of people who said they have no trust at all in the Hong Kong police has grown from 6.5 percent in early June — right before the protests started — to 48.3 percent in early September. 

Even before Tuesday, anger between residents and the police had been building. On Sunday, residents and restaurant workers emerged from the Wan Chai district to heckle and jeer at police and throw bottles at their vans.

As riot officers marched down the street to clear protesters and make arrests, some residents followed behind, shouting vulgarities repeatedly and mocking them by barking like dogs. 

Like Lau, the Hong Kong police sergeant, many police officers have turned to their admirers in mainland China for support. Lau began posting to the Chinese site Weibo in September and has since amassed a fan base of more than 600,000. An introductory blurb on his profile simply says, “I am Chinese.” 

By Wednesday afternoon, almost 500,000 people had liked Lau’s post describing his experience on the Great Wall, which he described as “more spectacular” than he could have imagined. Some praised him by the nickname they have adopted for the sergeant, “Bald Lau Sir.” 

“Mainland Chinese people welcome you and all of your family, and other Hong Kong police officers like you!” one commenter said. “Enjoy the beautiful rivers and mountains of our beloved motherland!” 

At least 10 other Hong Kong police officers have recently opened verified Weibo accounts and been flooded with mainland praise, including, in one case, a marriage proposal.

Lau and other officers have also given frequent interviews to fawning Chinese state media. Meanwhile in Hong Kong, police at protests have called reporters “cockroaches,” accused them of being “fake” journalists and increasingly blocked them from filming the police in action. 

In an interview with a Shanghai-based newspaper, Lau said he is mulling a move to mainland China, citing “better values” held by mainland Chinese students and worries over his children’s safety.