Pro-democracy protesters held twin rallies in Hong Kong on Sunday as China delivered fresh warnings about political unrest in the semi-autonomous city.
Thousands marched through two separate districts on Sunday afternoon, a day after police fired tear gas at demonstrators.
The city is preparing for a general strike on Monday.
China's official Xinhua news agency published a new commentary on Sunday saying "ugly forces" were threatening the country's "bottom line".
"The central government will not sit idly by and let this situation continue," the agency wrote.
Semi-autonomous Hong Kong has seen two months of protests and clashes triggered by opposition to a planned extradition law that quickly evolved into a wider movement for democratic reforms.
But authorities in Hong Kong and Beijing have hardened their stance. Dozens of protesters were charged with rioting last week while the Chinese military said it was ready to quell the "intolerable" unrest if requested.