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.
Israel carries out rare airborne raid in Lebanon; 16 killed in strikes
Israel launched airstrikes targeting Lebanon's Nabi Chit and nearby towns on Saturday, killing at least 16 people Lebanon's health ministry confirmed.
Israeli settler fatally shoots Palestinian in West Bank
An Israeli settler has shot dead a 27-year-old Palestinian man in the occupied West Bank on Saturday, the Palestinian Health Ministry said.
US skips congressional review to approve arms sale to Israel
The US State Department said on Friday it has approved a sale worth $151.8 million to Israel for munitions and munitions support, without submitting it for congressional review.
Flash floods in Nairobi kill 23, disrupt flights at major airport
Flash floods across Nairobi overnight has left at least 23 people dead, authorities said, adding that dozens of cars were swept away and flights at East Africa's biggest airport disrupted.
