Protesters have shot arrows and lobbed petrol bombs at police around a besieged Hong Kong university campus, with activists braced for a possible final police push to clear them.
Officers countered with dyed jets of liquid from water cannon after several individuals fired bows from rooftops at Polytechnic University on Sunday (local time) amid some of the most dramatic scenes in over five months of protests.
A police media liaison officer was hit in the leg by an arrow, police said in a statement. He remained conscious and was sent to hospital.
Huge fires had lit up the sky at the university in the heart of Kowloon district overnight as protesters hurled petrol bombs, some by catapult, and police fired volleys of tear gas to draw them into the open.
The AM Show's Hong Kong correspondent said on Monday it was the worst night of violence she has seen so far.
"Police have already said that they will use lethal weapons against protesters - that is completely new," said Grace Lee.
"We have seen them charging live ammunition in the past few months but for them to tell a group of protesters that they will open fire, that is an intense escalation," she continued.
She says the violence on both sides has increased.
"Police have been so heavy-handed with the protesters this week we've seen things escalate so incredibly much and protesters have been using anything in their disposal to fight back."
After a few quiet hours as protesters slept on lawns and in the university library, police fired fresh rounds of tear gas shortly after 10am. Activists threw petrol bombs in return, some igniting trees outside the campus.
"Police say the reason they need to end this immediately is a lot of the university students are using things from the chemistry labs to make bombs, and that's what they're afraid of," Lee told The AM Show.
Hours earlier, squads of Chinese soldiers in shorts and T-shirts, some carrying plastic buckets or brooms, emerged from their barracks in a rare public appearance to help residents clear debris blocking key roads.
As fresh violence erupted on Sunday, some soldiers in a base close to the university were seen monitoring developments with eye glasses, some dressed in riot gear with canisters on their chests.
Parts of the campus looked more like a fortress with barricades and black-clad protesters manning the ramparts with improvised weapons-like bricks, crates of fire bombs and bows and arrows at the ready.
"We are not afraid," said a year-three student Ah Long, who chose not to disclose his full name. "If we don't persist, we will fail. So why not (go) all in," he said.
Lee told The AM Show police are swarming the university buildings to try and get the protesters out, but reinforcements are showing up.
"Police are surrounding the university with the protesters still holed up inside, and now people who support the protesters are showing up outside police in a kind of counter protest," she said.
"Tonight is that big showdown that protesters have been expecting as they continue their stand against police- it's not clear how tonight will end but it is certainly very tense.
The campus is the last of five universities to remain occupied, with activists using it as a base to continue to block the city's central cross-harbour road tunnel.
The presence of China's People's Liberation Army (PLA) soldiers on the streets, even to help clean up, could stoke further controversy over Hong Kong's autonomous status at a time many fear Beijing is tightening its grip on the city.
Hong Kong did not request assistance from the PLA and the military initiated the operation as a "voluntary community activity", a spokesman for the city's government said.
Pro-democracy MPs condemned the PLA's actions, warning that under the city's Garrison Law the military must not interfere in local affairs unless asked by the government to help with disaster relief or public order.
The Asian financial hub has been rocked by months of demonstrations, with many angry at perceived Communist Party meddling in the former British colony, which was guaranteed its freedoms when it returned to Chinese rule in 1997.
Beijing denies interfering and has blamed the unrest on foreign influences.