HONG KONG - A mob of men wearing white and armed with wooden sticks and umbrellas attacked people dressed in black at a train station in a Hong Kong suburb near the border with China on Sunday (July 21).

The attacks injured more than 40 people, including a lawmaker and some journalists.

The attackers, who were wearing masks, appeared at Yuen Long Station at about 10.30pm, targeting unarmed passers-by wearing black, whom they believed to be anti-extradition protesters who were on their way home. Black is the preferred colour of demonstrators. Yuen Long borders the southern Chinese city of Shenzhen and is far from the main protest site in central Hong Kong.

In videos circulating online, the men in white went wild and chased people in black, some of whom tried to protect themselves with umbrellas and even a fire extinguisher.

During the bloody rampage, the group in white who some reports said was made up of triad gangsters, also went into a train carriage that had stopped at the platform of the station to beat up passengers.

The government said in a statement issued after midnight that some people had “congregated at the platforms of the MTR station and train compartments, attacking commuters”, which led to confrontations and injuries.

“This is absolutely unacceptable to Hong Kong as a society that observes the rule of law. The Hong Kong government strongly condemns any violence and will seriously take enforcement actions.”

Lawmaker Lam Cheuk-ting, who was among those injured, expressed outrage that the police did not show up an hour after he called them for help.

He said that when he reached the station, a group made up of locals and South Asian-looking men attacked him and that the attackers were aged between 20 and 60.

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Train operator MTR Corporation said in a statement that it had called the police at 10.45pm. Trains stopped calling into the station at about 11pm.

The police arrived at 11.15pm and were met with dozens of angry residents and protesters, local media reported.

When questioned why police took more than an hour to respond, police Pat Heung division commander Li Hon-man was reported by RTHK to have mockingly replied that he did not have a chance to look at his watch.

He also told reporters to stop questioning him, saying their questioning “wouldn’t scare him”, according to RTHK.

At around midnight, after the police left, the men in white forced open closed entrances at the MTR station and resumed their rampage.

At about 1am, riot police arrived at Nam Pin Wai village in Yuen Long, where a large group of men dressed in white and holding metal rods, had gathered.

After three hours, the riot police questioned several of the white-clad men and confiscated several metal bars. No one was arrested.

Earlier on Sunday, hundreds of anti-extradition protesters took their protest against the government to Beijing’s Liaison Office in the western part of Hong Kong island, Sheung Wan and Central.

They sprayed graffiti on the walls, defaced the office’s plaque and threw eggs at the building.

It was the seventh consecutive weekend of protests in Hong Kong and another that has ended in violent clashes. The protests were against a contentious extradition Bill that has been suspended indefinitely. They were sparked by Mrs Lam's move to amend existing legislation so as to allow Hong Kong to send suspects to other jurisdictions, including mainland China, to stand trial.

The liaison office spokesman late on Sunday strongly condemned protesters who vandalised the building and defaced the national emblem, saying the actions were a direct challenge to national sovereignty.

Chinese state news agency Xinhua said in an editorial on Monday that the attack on the liaison office was a “blatant challenge to the central government” and will not be tolerated.