HONG KONG -- Flights resumed Wednesday at Hong Kong's airport after two days of disruptions that descended into clashes with police, highlighting the hardening positions of pro-democracy protesters and the authorities in the semi-autonomous Chinese city. After nightfall, a new protest outside a police station in the city was dispersed as officers fired tear gas.

There was soul-searching in the protest movement, including the three dozen demonstrators who remained camped at the airport arrivals area. They asked travellers and the general public for forgiveness after their blockade turned into chaotic and frenzied violence.

While the movement's supporters still have street protests planned, it's unclear what their next move is or whether they will be able to find new rallying sites to keep the pressure on authorities.

Protesters spread pamphlets and posters on the floor in one section of the terminal but were not impeding travellers. Online, they also circulated letters and promotional materials apologizing for the inconveniences during the past five days of the airport occupation.

"It is not our intention to cause delays to your travels and we do not want to cause inconvenience to you," said an emailed statement from a group of protesters. "We ask for your understanding and forgiveness as young people in Hong Kong continue to fight for freedom and democracy."

The airport's management said it had obtained "an interim injunction to restrain persons from unlawfully and wilfully obstructing or interfering" with airport operations. It said an area of the airport had been set aside for demonstrations, but no protests would be allowed outside the designated area.

Additional identification checks were in place, but check-in counters were open and flights appeared to be operating normally. The demonstration resulted in more than 100 flight cancellations on Tuesday and about 200 on Monday.

Hong Kong police said they arrested five people during clashes at the airport Tuesday night.

Assistant Commissioner of Police Operations Mak Chin-ho said the men, aged between 17 and 28, were arrested for illegal assembly. Two were also charged with assaulting a police officer and possessing weapons as riot police sought to clear the terminal.

In Hong Kong's blue-collar Sham Shui Po neighbourhood, police fired tear gas Wednesday night at a group of protesters rallying outside a police station.

The protesters had gathered to burn phoney currency and incense as a way to show their opposition to the police during the month-long Hungry Ghost Festival, when offerings are made to ward off the spirits of ancestors.

Police armed with riot shields and batons marched through the neighbourhood. Officers carried warning flags and fired tear gas as they advanced, but protesters had already scrambled away.

More than 700 protesters have been arrested in total since early June, mostly men in their 20s and 30s, but also including women, teenagers and septuagenarians.

Mak said additional suspects from the airport were expected to be arrested, including those who assaulted an officer after stripping him of his baton and pepper spray, prompting him to draw his gun to fend them off.

Hong Kong law permits life imprisonment for those who commit violent acts or acts that might interfere with flight safety at an airport.

More than 74 million travellers pass through Hong Kong's airport each year, making it "not an appropriate place of protest," Mak said.

"Hong Kong police have always facilitated peaceful and orderly protests over the years, but the extremely radical and violent acts have certainly crossed the line and are to be most severely condemned," he said. "The police pledge to all citizens of Hong Kong that we will take steps to bring all culprits to justice."

That was backed up by a statement on a new government website set up to provide the latest information on the crisis, which said, "The police will take relentless enforcement action to bring the persons involved to justice."

Hong Kong airline Cathay Pacific said it had cancelled 272 flights in the past two days, affecting more than 55,000 passengers, while 622 departures and arrivals went ahead.

Cathay also said it has fired two pilots in an apparent response to their involvement in activity related to pro-democracy protests. They included one pilot who is "currently involved in legal proceedings." The airline said earlier this week one of its pilots has been charged with rioting after being arrested during a protest.

It said the second fired pilot "misused company information," but gave no other details. The Hong Kong Free Press reported the pilot posted a photo of a cockpit screen on an online forum used by protesters.

The airport disruptions grew from a summer of demonstrations aimed at what many Hong Kong residents see as an increasing erosion of the freedoms they were promised in 1997 when Communist Party-ruled mainland China took over what had been a British colony.

While Hong Kong's crucial travel industry suffers major losses, the city's reputation as a well-regulated centre for finance is also taking a hit. At least 21 countries and regions have issued travel safety alerts for their citizens travelling to Hong Kong, saying protests have become more violent and unpredictable.

The demonstrators demand that Hong Kong leader Carrie Lam step down and scrap proposed legislation under which some suspects could be sent to mainland China, where critics say they could face torture and unfair or politically charged trials.

Lam has rejected calls for dialogue, saying the protesters were threatening to push their home into an "abyss."

The Chinese Cabinet's liaison office in Hong Kong said the protesters had "entirely ruptured legal and moral bottom lines" and would face swift and severe repercussions under Hong Kong's legal system.

"Their behaviour shows extreme contempt for the law, seriously damages Hong Kong's international image and deeply hurts the feelings of the broad masses of their mainland compatriots," the statement said.

Most of the protesters left the airport Tuesday after riot police tried to enter the terminal, fighting with demonstrators who barricaded entrances with luggage carts. The brief clash led to several injuries.

The violence included protesters beating up at least two men they suspected of being undercover Chinese agents. Airport security appeared unable to control the crowd, and paramedics later took both men away. Police have acknowledged using "decoy" officers, and some protesters over the weekend were seen being arrested by men dressed like demonstrators -- in black and wearing face masks.

Hu Xijin, editor-in-chief of the Global Times, identified one of the men as a journalist at the nationalistic Chinese tabloid.

"Fu Guohao, reporter of GT website is being seized by demonstrators at HK airport," Hu wrote on his Twitter account. "I affirm this man being tied in this video is the reporter himself. He has no other task except for reporting."

The protesters apologized that some of them had become "easily agitated and overreacted." On posters, the demonstrators said they have been "riddled with paranoia and rage" after discovering undercover police officers in their ranks.

Earlier this week, the central government in Beijing issued an ominous characterization of the protest movement as something approaching "terrorism" -- a label it routinely applies to nonviolent protests of government policies on the environment or in minority regions such as Xinjiang and Tibet.

Satellite photos show what appear to be armoured personnel carriers and other vehicles belonging to the China's paramilitary People's Armed Police parked in a sports complex in the city of Shenzhen, across the border in Hong Kong, in what some have interpreted as a threat from Beijing to use increased force against protesters.

The pictures collected on Monday by Maxar's WorldView show 500 or more vehicles sitting in and around the soccer stadium at the Shenzhen Bay Sports Center.

U.S. President Donald Trump tweeted that U.S. intelligence believes that the Chinese government is moving troops to its border with Hong Kong and that, "Everyone should be calm and safe!"

While China has yet to threaten using the army -- as it did against pro-democracy protesters in Beijing in 1989 -- recent police exercises across Hong Kong's border with mainland China were a sign of its ability to crush the demonstrations, even at a cost to Hong Kong's reputation as a safe haven for business and international exchange.

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Associated Press video journalist Katie Tam in Hong Kong and writer Kelvin Chan in London contributed to this report.