Police fired pepper spray in running battles with thousands of demonstrators on the streets of Hong Kong on Sunday as they tried to encircle China's representative office in protest against Beijing's attempts to stop independence activism.
Streets filled with mostly young people, many dressed in black, brought to mind weeks of pro-democracy marches in 2014.
This time they were protesting before a ruling due on Monday that is expected to bar two lawmakers from taking office in Hong Kong's legislature.
The situation is seen by many of the territory's legal and political elite as one of the biggest tests of Hong Kong's independent rule of law that the global financial hub has faced since its handover to China nearly two decades ago.
Critics say the ruling from a top committee of China's parliament essentially circumvents local courts.
The two lawmakers, Yau Wai-ching and Baggio Leung, had pledged allegiance to the "Hong Kong nation" and displayed a "Hong Kong is not China" banner during a swearing-in ceremony for the city's legislative council in October. Their oaths were not accepted and their right to retake them is being challenged in the local courts by the autonomous Hong Kong government.
Close to a thousand police officers, some with riot shields and batons, and some behind temporary metal barricades, were deployed to prevent protesters surging towards the central government's Liaison Office, viewed by many as a symbol of Beijing's increasing influence on the free-wheeling city.