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.
Winter storm hits central US
A winter storm brought snow, ice and freezing temperatures to a broad swath of the U.S. on Sunday, with some 60 million people across more than a dozen states from Kansas to New Jersey under winter weather warnings and advisories.
Ukrainian forces launch major attack in Kursk region
Ukrainian forces have launched a major new attack in Russia's western Kursk region, Russian military bloggers reported on Sunday.
South Koreans protest as Yoon arrest deadline looms
Thousands braved heavy snow in Seoul on Sunday to rally for and against arresting impeached President Yoon Suk Yeol, as South Korea's political crisis appeared headed toward another high-stakes confrontation.
Syrian foreign minister in Doha to meet senior Qatari officials
Syrian Foreign Minister Asaad Hassan al-Shibani, appointed by the country's new rulers, arrived in Qatar on Sunday to meet senior Qatari officials.
Massive winter storm to hit US from Plains to East Coast
Millions of Americans from the Plains to the East Coast faced the threat of blizzards, heavy snow, treacherous ice and freezing rain through Monday, the National Weather Service said on Saturday.
