Chinese state media have reported that “Foreign forces” are seeking “to hurt China by trying to create havoc in Hong Kong”, after mass protests in the territory.
On Sunday, hundreds of thousands of people rallied against a proposed law critics fear could let China target political opponents in Hong Kong.
Clashes later erupted between hundreds of demonstrators and police.
The government said plans will go ahead for the second reading of the extradition bill on Wednesday.
Organisers estimate that one million people took part in the march, however police put the figure at 240,000 at its peak.
If the organisers’ estimate is confirmed as correct, it would be the largest demonstration in Hong Kong since the territory was handed over to China by the British in 1997.