Authorities in Hong Kong warned that the situation in the territory is becoming "very dangerous."
The comments came after police fired a warning shot during protests on Sunday. It was the first time live ammunition has been used since protests began. Security forces also used water cannons as pro-democracy protesters turned out for the 12th straight weekend.
Demonstrations were sparked by an extradition bill but have since morphed into broader anti-government protests. Police have arrested over 700 people since the protests began in June.