Tens of thousands of demonstrators clashed with Hong Kong police Saturday, protesting an attack by gang members on pro-democracy supporters last week.

Riot police in the Yuen Long area fired tear gas into the crowd, which threw rocks and bottles at them from behind barricades made from furniture and umbrellas.

Police have been under fire for failing to protect commuters from beatings by suspected triad members in a train station.

Some believe cops colluded with the gangs to suppress the demonstrations.

Protesters have been demanding a probe of police violence and the ouster of the territory’s leader, Carrie Lam.