Masked men attacked passengers after storming a train station in Hong Kong's Yuen Long district on Sunday.
Police say dozens of people are injured with one person in critical condition.
It comes after the latest pro-democracy rally in the centre of Hong Kong.
Demonstrations were also protesting against a controversial bill that allows extraditions to mainland China.
It's still unclear who the mob was or why the attacked the passengers.
At least 47 dead in eastern Indonesia after magnitude 7.7 quake
At least 47 people were killed after a magnitude 7.7 earthquake and dozens of aftershocks struck off eastern Indonesia on Saturday, the National Disaster Mitigation Agency (BNPB) said in its latest statement.
Kuwait, Bahrain strongly condemn Iranian attack on ADNOC vessels
Kuwait and Bahrain on Saturday expressed their strong condemnation of the Iranian attack against vessels affiliated with the UAE's Abu Dhabi National Oil Company (ADNOC) while transiting the Strait of Hormuz.
Yemen's Mocha port halts operations after Houthi attacks, port director says
Yemen's Mocha port has suspended commercial and maritime operations after being hit by more than 25 missiles in Houthi attacks over recent days, the port's director said on Saturday.
Morocco arrests 111 migrants headed for Spain's Ceuta in security crackdown
Moroccan police arrested at least 111 people on Saturday as they tried to enter Spain's North African enclave of Ceuta, amid tightened security on both sides of the border after social media posts called for another mass migrant crossing.
