Hong Kong police have detained six men, some with links to triads, following a violent attack on pro-democracy protesters and bystanders at a subway station where dozens were injured.
Senior police official Chan Tin-chu said the men, aged between 24 and 54, were being held for "unlawful assembly" and will be investigated for taking part in the attack late Sunday night.
He said police are still investigating the motive for the attack and further arrests are expected.
A gang of white-clad men beat up anti-government protesters and others inside a subway station with metal rods and wooden poles, injuring 45 people including one in critical condition.
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The police have been criticised for a slow response, and Hong Kong leader Carrie Lam denied the government colluded with the assailants.
The attack unfolded after several thousand pro-democracy activists descended on China's representative office in the city, clashing with police.
Some of the victims had come from the demonstration - the latest in a series of protests over the past two months, which have seen millions take to the streets in a show of force against Lam.
