Hong Kong awoke to what is expected to be a day of relative calm following a violent night in which protesters set fire to metro stations and vandalised buildings, including an office of China's official news agency Xinhua.

More than 200 people were arrested on overnight, in one of the worst outbreaks of violence in recent weeks as around five months of protests show no signs of abating.

EPA

Demonstrators are angry at perceived Chinese meddling with Hong Kong's freedoms since the city returned from British to Chinese rule in 1997, a charge which China denies.

Cat-and-mouse clashes between riot police and demonstrators continued into the early hours of Sunday morning after police broke up an assembly of thousands on Saturday afternoon by firing tear gas into a park.

AP

With no major demonstrations planned for Sunday, a clean-up operation was underway at the Chinese state-owned Xinhua News Agency offices, one of the buildings targeted by groups of black-clad protesters who fled the park to the business district, hurling petrol bombs and bricks along the way.

While protesters have previously vandalised buildings of mainland Chinese firms or those perceived as pro-Beijing, the targeting of Xinhua as a key symbol of the mainland's presence in Hong Kong is one of the most direct challenges to Beijing yet.

The news group has denounced the attack on its office, describing it as "barbaric", with the Hong Kong Journalists Association calling for an end to violence against the media.

AFP

When Reuters visited early Sunday, some cleaning staff could be seen sweeping glass from the floor through broken doors and windows, as tourists curiously eyed the destruction.

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Hong Kong police said they had arrested more than 200 people overnight for offences including unlawful assembly, possession of offensive weapons, criminal damage, and wearing masks which is now illegal under a revived colonial-era emergency law.

Police fired tear gas, rubber bullets and deployed a water cannon at protesters during Saturday and early Sunday, they said, as the violence spilled from Hong Kong island across the water to the northern Kowloon side.

Loathed by Beijing

Among those calling for people to come out on Saturday was Joshua Wong, one of the city's most prominent activists who was barred earlier this week from standing in upcoming local elections.

"Exercising freedom of assembly has become increasingly difficult as police in HK holds tighter grip in recent months. Yet we're not giving up our constitutional rights," he wrote on Twitter.

AFP

Wong is loathed by Beijing with state media often branding him a "separatist" and a "traitor" because he campaigns for greater autonomy for Hong Kong.

He denies seeking independence and says he simply campaigns for the democratic freedoms and autonomy Beijing promised Hong Kong for 50 years after the 1997 handover by Britain.

Other people who advocate greater autonomy have been allowed to stand in the elections later this month.

Beijing runs Hong Kong under a "one country, two systems" model that grants the city freedoms unheard of on the authoritarian mainland.

But many activists fear those freedoms are being eroded by a resurgent Beijing, particularly since President Xi Jinping came to power.

This summer's protests in which millions marched were sparked by a now-abandoned attempt to allow extraditions to the authoritarian mainland.

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But as Beijing took a hardline the movement snowballed.

Protesters are demanding an inquiry into the police, an amnesty for those arrested and fully free elections.

Over the month's protests have become increasingly violent, with smaller groups of hardcore activists throwing petrol bombs and bricks as well as vandalising pro-China businesses.

Police have responded with ever-increasing arrests, tear gas and rubber bullet volleys while crowd beatings of people on both sides of the ideological divide have become commonplace.

With wires...