Hong Kong leader Carrie Lam's biggest concession yet to protesters did little to stem scenes of violence that have become the norm on weekends in the Asian financial hub.

Small pockets of demonstrators Sunday set fires, vandalized subway stations and set up barricades downtown after tens of thousands marched to the U.S. Consulate to appeal for help from President Donald Trump. Riot police cleared roads and subway stations, fired tear gas and made arrests of black-clad protesters wearing masks and hard hats.

On Saturday in Kowloon, protesters burned a barricade in a busy shopping and residential area. A total of 19 people were injured in clashes between demonstrators and police, and officers were criticized for using pepper spray on reporters and photographers.