At least 45 people went to hospital with one man in critical condition and five in serious condition after a group of armed people attacked passengers and people in the Yuen Long MTR station, the government said.
The group clad in white t-shirts and masks were armed with sticks and targeted those wearing black, apparently in the belief that their victims had been to the anti-extradition bill protests earlier in the day on Hong Kong Island.
While the MTR Corporation announced in a statement that it had called the police at 10.45pm, there were multiple claims that it took officers far too long to respond to the violence and officers were met with an angry crowd when they did arrive.
The armed group had rampaged through the station, some people did fight back, using umbrellas and even a fire extinguisher at one point.
But most of those attacked were left visibly shaken and some with bloodied faces and heads. Among the injured were lawmaker Lam Cheuk-ting and media people.
Footage posted on social media showed ugly scenes, with people even assaulted inside a train at a station platform. Some footage showed groups of people surrounding individuals and beating them with sticks and umbrellas.
The police eventually appeared to have left the scene again, and while trains had already stopped serving Yuen Long, the station closed early, before midnight, at the request of the police.
But fighting erupted again and several men in white t-shirts later forced open the shutters of the station and went back inside.
Police Pat Heung division commander Li Hon-man, who arrived at the scene, dismissed with disdain reporters' questions about police response.
When questioned why police took more than an hour to respond, Li mockingly replied that he didn't have a chance to look at his watch.
He also told reporters to stop questioning him, saying their questioning "wouldn't scare him".
By around 1.30am, riot police officers were out in force in Yuen Long.
Men in white t-shirts were still milling around a village not far from the station, many of them wearing masks and helmets and carrying what appeared to be metal bars.
Last updated: 2019-07-22 HKT 10:19
At least 45 hurt in Yuen Long attack, one critical
2019-07-22 HKT 01:34
2020-07-03 HKT 17:15
2020-07-02 HKT 13:26
2020-06-30 HKT 14:26
2020-06-29 HKT 18:08
2020-06-27 HKT 14:50
2020-06-27 HKT 14:26
2020-06-26 HKT 15:09
2020-06-25 HKT 21:56
2020-06-25 HKT 17:23
2020-06-24 HKT 15:57
2020-06-23 HKT 23:29
2020-06-23 HKT 13:13
2020-06-23 HKT 12:31
2020-06-22 HKT 18:21