A police station in Hong Kong became the target of protesters’ ire as rallies in two different parts of the city converged into one on Sunday.

Following a rally in the Tseung Kwan O area, some protesters used what appeared to be a long, home-made slingshot to hurl rocks, bricks and other objects at a police station.

They shattered multiple glass windows, authorities said.

Hong Kong Protests
A protester throws a brick at the police station (Vincent Thian/AP)

Demonstrators elsewhere also began to barricade and block roads.

Police said earlier in the day they had arrested more than 20 people for offences including unlawful assembly and assault after protest marches on Saturday devolved into now routine standoffs between protesters and law enforcement.

As has been the pattern during two months of mass pro-democracy demonstrations in the Chinese territory, Sunday’s rallies started off peacefully.

At one park on Hong Kong Island, a flautist and a trumpeter played Do You Hear the People Sing? from the musical Les Miserables, which has become a rallying song for protests.

Protesters believe China’s government and the administration of Hong Kong chief executive Carrie Lam are eroding the civil liberties and political autonomy promised when the former British colony was returned to China in 1997.

“We are not just another Chinese city – we are Hong Kong,” said Cara Lee, 53, an insurance agent who was attending her 13th demonstration.

“I feel ashamed because for a long time we didn’t do anything,” she said.

“But now we are awake. I have to speak out for the next generation. It’s our moral responsibility.”

Hong Kong Protests
A protester throws back a tear gas canister during clashes on Saturday (Vincent Thian/AP)

On Saturday, a protest march in the territory’s northern area of Kowloon erupted in clashes with police after some marchers walked off the government-approved route and into separate areas.

Police said some protesters threw petrol bombs, bricks and glass bottles and refused to disperse.

Some blocked streets while others surrounded two different police stations, damaging vehicles parked inside one lot.

Residents in one neighbourhood banded together with protesters and surrounded a police station, yelling at riot police to leave.

Protesters are demanding an independent investigation into complaints of police abuse and the government response to an attack in a train station that injured 44 people.

They also want Ms Lam to resign.

Activists have called for a city-wide general strike on Monday.

Hong Kong residents increasingly accuse China’s ruling Communist Party of encroaching on their liberties.

Those fears have been fuelled by the arrests of booksellers and activists in Hong Kong.

During the rally on Saturday, some protesters scaled a flag pole, removed the Chinese flag and flung it into the iconic Victoria Harbour.

Former Hong Kong leader CY Leung offered one million Hong Kong dollars (£105,000) for information about who threw the flag into the water.

The act will provoke “enormous resentment from the entire nation”, he said.