Hong Kong leader Carrie Lam has warned anti-government protesters not to push the city into an "abyss", in an emotional press conference on Tuesday.
Ms Lam said Hong Kong had "reached [a] dangerous situation" and that violence during protests would push it "down a path of no return".
She was met with hostility as she dodged questions by reporters, who repeatedly shouted and cut her off.
Meanwhile protests are continuing for a fifth day at the city's busy airport.
Mass unrest has rocked Hong Kong for 10 weeks and shows no signs of abating.
Large protests started in response to a proposed extradition bill, which has now been suspended, but have evolved into a more demanding pro-democracy movement.
Protests are fuelled by fear that the freedoms Hong Kong enjoys as a special administrative region of China are being eroded.
Ms Lam's comments came a day after hundreds of flights had to be cancelled when thousands occupied the city's international airport. Dozens more have been cancelled on Tuesday, as demonstrators continue to gather.
What's happening at the airport?
Authorities said on Tuesday that operations have resumed, but warned flights would still be affected.
Flagship carrier Cathay Pacific said it had cancelled more than 200 inbound and outbound flights, and would run only a limited number for connecting passengers.
Footage from inside shows hundreds sitting inside terminal buildings, including some obstructing departure gates.
Some held signs apologising to passengers for the inconvenience. Others wore bandages and brandished slogans criticising the police's deepening crackdown on the unrest.
Doctors at Hong Kong's Queen Elizabeth Hospital have also staged a small sit-in protest opposing police violence, local media report.
What did Carrie Lam tell the media?
Ms Lam appeared close to tears at her Tuesday press conference as she called on Hong Kong residents to put aside their differences.
"Take a minute to think, look at our city, our home - do you all really want to see it pushed into an abyss?" AFP quoted her as saying.
Her comments echoed similar remarks by an official from the Chinese Liaison Office in Hong Kong, who said the city would slide "into a bottomless abyss if the terror atrocities are allowed to continue".
Local journalists unleashed a barrage of questions in Cantonese and English, many condemning Ms Lam's response to the unrest.
"You blame your own political misjudgement on others, and refuse to acknowledge your mistakes," one journalist said, according to AFP.
"When will you accept political responsibility to end citizens' fear?... When will you be willing to step down? When will you tell the police to stop?" Hong Kong's public broadcaster, RTHK, reportedly asked.
Ms Lam evaded a question on whether she had the autonomy to completely withdraw the extradition bill, a key demand of protesters, saying she had answered it in the past.
She said she was "heartbroken" by reports of serious injuries at last weekend's protests, but appeared to defend the police from claims they used disproportionate force, saying they were acting under "extremely difficult circumstances".
Footage captured on Sunday showed police shooting non-lethal ammunition at protesters from close range.