Huge protest crowds thronged Hong Kong on Sunday as anger swells over plans to allow extradition to China, a proposal that has sparked the biggest public backlash against the city's pro-Beijing leadership in years.

Police said four successful recent drug busts had led to the confiscation of a huge haul of narcotics, including more than 1,000 kilograms of marijuana, three kilograms of highly concentrated hashish oil, over 100,000 meth-amphetamine pills, some 5,300 grams of crystal meth or “ice”, and 850 grams of ketamine.