Hong Kong's opposition Democratic Party is investigating attacks by suspected triad gangsters on train passengers on Sunday, after a night of violence opened new fronts in the political crisis now deepening across the city. Screams rang out when men, clad in white t-shirts and some armed with poles, flooded into the rural Yuen Long station and stormed a train, attacking passengers, according to footage taken by commuters and Democratic Party lawmaker Lam Cheuk-ting. Some passengers had been at an anti-government march and the attack came after several thousand activists surrounded China's representative office in the city, later clashing with police.