“Sorry for the inconvenience, we are fighting for the future of our home,” read a banner held by some of the hundreds of protesters who had returned to the arrivals hall.
While the protest at the airport was peaceful, out on the streets the incidents of violence have become more frequent.
During the weekend protests, website Hong Kong Free Press showed footage of one arrest that appeared to include officers in plain clothes pinning a demonstrator pressed to the ground.
The young man, who said his name was Chow Ka-lok and asked for a lawyer, was shown with a bleeding head wound and said he had a broken tooth, the Press Association reports.
Police have also reported injuries among their ranks, including eye irritation from laser pointers, burns from petrol bombs and bruises and cuts from flying.
Protesters hurled bricks at officers and ignored warnings to leave before tear gas was deployed in the Sham Shui Po area, police said, calling a march there an “unauthorised assembly”.
Tear gas was also deployed in central Hong Kong on both sides of Victoria Harbour, in the Tsim Sha Tsui area on the Kowloon side and in Wan Chai on Hong Kong Island.
Lam held a press conference on Monday – at a government headquarters complex fortified with six-foot high water-filled barricades.
Despite calls for her to step down, Lam was defiant. “My responsibility goes beyond this particular range of protest,” she said, adding that violence had pushed the territory into a state of “panic and chaos”.
“Take a minute to look at our city, our home. Can we bear to push it into the abyss and see it smashed to pieces?”
More ominously, Hong Kong authorities have publicly demonstrated water cannon.