Hong Kong pro-democracy activists recaptured parts of a core protest zone from police early yesterday after hours of turmoil that the city's police chief warned undermined order and jeopardised public safety.

Dozens of people were injured in the skirmishes, including 18 police, which raged through the night as several thousand protesters squared off again police in the densely populated Mong Kok district.

At least 33 people were arrested, Hong Kong public broadcaster RTHK reported.

Police used batons and pepper spray, and scuffled violently with activists, but they were eventually forced to pull back less than 24 hours after they re-opened most of the area to traffic.

The protests have been going on for three weeks and pose one of the biggest political challenges for China since the crushing of pro-democracy demonstrations in Beijing in 1989.

At least 33 people were arrested

Hong Kong Police Commissioner Andy Tsang broke three weeks of public silence to say his force had been “extremely tolerant” but had failed to stop protesters becoming more “radical or violent”.

“To these protesters, you may think that your illegal acts have prevented the police in going about our duties, disrupted our deployments and even forced us to retreat,” Tsang told a news conference.

“Superficially, that may be the case. But let me tell you this: these illegal acts are undermining the rule of law, undermining (what) Hong Kong has been relying on to succeed.”

After police retreated, demonstrators swiftly stacked up barricades made out of packing crates and fences. Tsang said the reoccupation of the area “seriously undermined public order and seriously jeopardised public safety”.

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