Protesters in Hong Kong threw petrol bombs and police fired tear gas Saturday in renewed clashes over anti-government grievances.

Reporters saw at least one person arrested after violence erupted following an afternoon march by several thousand people in Tuen Mun, a district in the northwest of the Chinese territory.

Hong Kong is in the fourth month of sometimes violent protests that occur every weekend. They started with opposition to a proposed extradition law and have expanded to include demands for greater democracy.

Most protesters in Tuen Mun were peaceful but some threw petrol bombs and bricks toward police who faced them down the street. They appeared to fall short of the police and there was no indication anyone was hit.

Police with anti-riot helmets and shields responded by firing tear gas.

In the evening, protesters gathered at a shopping mall in another district, Yuen Long. Some threw petrol bombs in the street but there was no indication anyone was injured.

Elsewhere, scuffles were reported as government supporters heeded a call by a pro-Beijing member of the Hong Kong legislature to tear down protest posters at subway stations.

The events are an embarrassment for China’s Communist Party ahead of October 1 celebrations of its 70th anniversary in power.

Hong Kong’s government has cancelled a fireworks display that day, citing concern for public safety.

The protesters in Tuen Mun marched about 2km from a playground to a government office building. Many were dressed in black and carried umbrellas, a symbol of their movement.

Protesters chanted, “Reclaim Hong Kong!” and “Revolution of our times!”

Most were peaceful but some took down a Chinese flag from a pole outside a government office and set fire to it. Protesters also set up barricades to block traffic.

A government statement said protesters caused unspecified damage to the Tuen Mun light rail station and threw objects onto the tracks.

An organiser quoted by government broadcaster RTHK criticised police for sending armed anti-riot officers. That will “only escalate tension between protesters and police”, the organiser, Michael Mo, was quoted as saying.

Hong Kong’s leader, chief executive Carrie Lam, has agreed to withdraw the extradition bill. But protesters are pressing other demands, including an independent investigation of complaints about police violence during earlier demonstrations.

Protesters complain Beijing and Lam’s government are eroding the “high degree of autonomy” and western-style civil liberties promised to the former British colony when it was returned to China in 1997.

The protests have begun to weigh on Hong Kong’s economy, which already was slowing due to cooling global consumer demand.

The Hong Kong airport said passenger traffic fell in August. Business is off at hotels and retailers.

Police refused permission for Saturday’s march but an appeal tribunal agreed to allow a two-hour event.