Police in Hong Kong say they have arrested 19 people in connection with disturbances surrounding pro-democracy protests.
Some of those held are said to be suspected members of Triads, or Chinese criminal gangs.
Activists have complained of mobs intimidating them.
The protests have been largely peaceful since police and demonstrators clashed last weekend.
But there have been scuffles amid tense scenes in a suburb where criminal gangs are suspected to be based.
Students have pulled out of talks on political reform with the government.
Tens of thousands of demonstrators have been calling on Hong Kong’s chief executive to step down and demanding that China ditch its decision to handpick election candidates.
The police were said to be absent on Saturday morning, arguing they have exercised “dignity and restraint”.
Amnesty International has accused them of failing to protect pro-democracy protesters from attacks by counter demonstrators.