Authorities at Hong Kong airport suspended check-ins on Tuesday after pro-democracy protesters blocked the terminal for a second day, but reversed a previous statement saying that all departing flights had been cancelled.
"Terminal operations at Hong Kong International Airport have been seriously disrupted, and all check-in processes have now been suspended," the airport said.
"Members of the public are advised not to come to the airport... "All passengers are advised to leave the terminal buildings as soon as possible."
An estimated 5,000 protesters blocked the terminal on Monday, forcing flights to be suspended in the latest move in 10 weeks of protests.
Some passengers challenged protesters over the delays as tempers began to fray, while the demonstrators, employing a Chinese term of encouragement, chanted, "Hong Kong people — add oil!"
Small numbers of police headed into the terminal Tuesday evening to a chorus of boos from those conducting the sit-in, local reporters claimed, clearing barricades outside on their way in.
Flag carrier Cathay Pacific urged passengers to postpone non-essential travel on Tuesday and Wednesday.
The airline, whose British heritage makes it a symbol of Hong Kong's colonial past, is also in a political bind.
China's civil aviation regulator demanded it suspend personnel who joined or backed the protests from flights into its airspace, pushing its shares to a 10-year low on Monday and lower still on Tuesday.
The airport closure added to that pressure, though some firms benefited from the chaos.
Shares in Shenzhen Airport Co Ltd surged 10 per cent, the maximum allowed on the index, buoyed by potential flight diversions.
Flagship carrier Air China said it would add capacity on its Beijing-Shenzhen route, as a result of the disruptions.
Other Chinese airlines have offered passengers a free switch of destination from Hong Kong to nearby locations such as Guangzhou, Macau, Shenzhen or Zhuhai.
Hong Kong airport said it would attempt to reschedule flights on Wednesday, depending on the level of disruption from protesters.
But in a sign the island's leaders are growing increasingly concerned with the ongoing protests, the city's Chief Executive said Hong Kong is in a state of "panic and chaos", the city's embattled leaders on Tuesday vowed to press on amid calls to stand down after weeks of protests and a tumbling stock market.
Unrest has roiled the former British colony for 10 weeks this summer, as thousands of residents chafe at a perceived erosion of freedoms and autonomy under Chinese rule.
The increasingly violent demonstrations have plunged the Asian financial hub into its most serious crisis in decades, presenting Chinese leader Xi Jinping with one of his biggest challenges since he came to power in 2012.
For a fifth day, protesters occupied the arrivals hall at Hong Kong airport, shut down in an unprecedented move on Monday that forced hundreds of flight cancellations. Beijing likened the demonstrations in Hong Kong to terrorism.
"Take a minute to look at our city, our home," Chief Executive Carrie Lam told a news conference at the government headquarters complex, fortified with 6-foot high water-filled barricades after protesters have stormed government buildings.
"Can we bear to push it into the abyss and see it smashed to pieces?" she added, her voice wavering.
As she spoke, the benchmark Hang Seng index hit a seven-month low. By lunchtime, it had dropped nearly 2 per cent, dragging down markets across Asia. It has fallen 6 per cent since the protests began in June.
UN Human Rights Commissioner Michelle Bachelet warned Hong Kong authorities Tuesday against using heavy-handed tactics to quash the protests, adding it had reviewed "credible evidence" of such acts.
"Officials can be seen firing tear gas canisters into crowded, enclosed areas and directly at individual protesters on multiple occasions, creating a considerable risk of death or serious injury," a spokesman for Ms Bachelet said.
The protests began as opposition to a now-suspended bill that would have allowed extradition to mainland China for those facing criminal charges, but have swelled into wider calls for democracy.
Demonstrators say they are fighting the erosion of the "one country, two systems" arrangement enshrining some autonomy for Hong Kong when China took it back from Britain in 1997.
They want Ms Lam to resign but she says she would stay.
"My responsibility goes beyond this particular range of protest," she said. Violence has pushed the territory into a state of "panic and chaos", Ms Lam said.
"I, as the chief executive, will be responsible to rebuild the Hong Kong economy, to engage as widely as possible, listen as attentively as possible to my people's grievances and try to help Hong Kong to move on."
She has dodged questions about stepping down despite vowing when she took office in 2017 that she would leave if ever she lost the faith of the people of Hong Kong.
She did not respond to repeated requests to clarify if she had the power to withdraw the extradition bill to satisfy a major demand by protesters, or if she required Beijing's approval.
On Monday China said the protests had reached a critical juncture, after a weekend of street clashes in which police and protesters appeared to toughen their resolve.
Police fired tear gas at the black-shirted crowds in districts on Hong Kong island, Kowloon and the New Territories.
A senior Chinese official said "sprouts of terrorism" were emerging in Hong Kong, given instances of violent attacks against police officers.
Hong Kong legal experts say Beijing might be paving the way to use antiterror laws to restrain the protesters.