Hong Kong police fired tear gas and rubber bullets in fresh clashes with protesters after a general strike caused transport chaos on Monday, and as night fell in the Asian financial hub thousands of activists blocked roads in several districts.

The latest protests surpassed all the earlier shows of dissent for scale and intensity, escalating after Hong Kong’s Beijing-backed leader warned that the city is on the verge of an “extremely dangerous situation” and represented a challenge to China’s sovereignty.

What started several months ago as demonstrations over an extradition bill that would have allowed people to be sent to mainland China for trial have now evolved into a much broader backlash against the city’s government and its political masters in Beijing.

As some train and bus services resumed, tens of thousands of demonstrators fanned out across several districts, and there were running battles with riot police as some activists besieged police stations. Thousands of black-clad protesters later occupied roads in the Admiralty district near government buildings for several hours before moving to other areas. By nightfall, protests continued across the city.

Earlier, speaking to the media for the first time in two weeks, Beijing-backed leader Carrie Lam remained defiant as she rejected calls from protesters demanding her resignation, saying the government would be resolute in maintaining law and order. She warned that the protests were putting the former British colony on a path of no return and had hurt its economy.

“They claim they want a revolution and to restore Hong Kong. These actions have far exceeded their original political demands,” said a stern-faced Lam, flanked by senior members of her administration.

In an upmarket shopping mall in Sha Tin, scores of shops were shuttered, including clothing retailer H&M as well as luxury brands Chanel and Dior.

Protesters in the shopping centre chanted, “Strike! Support to the end.”

Many stores in the bustling shopping district of Causeway Bay were closed as well as businesses close to the protests.