Protesters in Hong Kong trampled a Chinese flag, vandalised a subway station and set a fire across a wide street on Sunday, as pro-democracy demonstrations took a violent turn once again.
Other pro-democracy protesters in Hong Kong rallied inside a mall, but plans to disrupt the airport did not materialise.
Authorities reduced rail and bus links to the city's airport while police stepped up security checks in a bid to scupper any attempt on the bustling transport hub.
The airport - the world's eighth busiest - has become a frequent target for demonstrators pushing for greater democratic rights and police accountability.
Online forums used by the largely leaderless movement had called for a "stress test" of the airport on Sunday, code for disrupting travel links or occupying buildings.
But the security rollout and reduced travel links appeared to put protesters off massing at the airport.
Instead thousands gathered inside a mall in the northern town of Sha Tin to sing protest songs and make origami cranes, the latest rally in what has now been 16 consecutive weekends of protests and clashes.
The violence has hit pockets of Hong Kong at different times over more than three months, allowing life to go on as normal for the vast majority most of the time.
But pictures of petrol bombs and street clashes broadcast worldwide present a huge headache for Beijing just days before the 70th anniversary of the founding of the People's Republic on October 1.
The Hong Kong government has already called off a big fireworks display to mark the day in case of further clashes. China, which has a People's Liberation Army garrison in Hong Kong, has said it has faith in Hong Kong leader Carrie Lam to solve the crisis.
Police fired tear gas to disperse pro-democracy protesters who threw petrol bombs in two new towns on Saturday after pro-China groups pulled down some of the "Lennon Walls" of anti-government messages. There were violent clashes elsewhere in the city.
Police condemned the violence and said there had been many serious injuries in fights between people of "different views".
"They threw petrol bombs at police vehicles and police officers, and even attempted to snatch the revolver of a police officer," police said in a statement on Sunday.
The protests picked up in June over legislation, now withdrawn, that would have allowed suspects to be sent to mainland China for trial. Demands have since broadened into calls for universal suffrage.
The protesters are angry about what they see as creeping Chinese interference in the former British colony, which returned to China in 1997 under a "one country, two systems" formula intended to guarantee freedoms that are not enjoyed on the mainland.
China says it is committed to the "one country, two systems" arrangement and denies meddling. It has accused foreign governments including the United States and Britain of inciting the unrest.