Dozens injured after masked men storm a train station to attack pro-democracy protesters.Read more
BBC News China
Trading on China's new Nasdaq-style technology board began on Monday and got off to a solid start.
Most shares on the so-called Star market, operated by the Shanghai Stock Exchange, surged on debut.
Last year China said it would launch the technology-focused trading board, as it sought to build on Shanghai's role as a global financial hub.
It marks a significant step in the country's bid open its economy and markets.
Footage showed masked men, all in white T-shirts, attacking people on platforms and inside train carriages at Yuen Long station.
Footage shows tear gas being fired as riot police march towards protesters.