China's President Xi Jinping late Thursday warned deepening protests in Hong Kong threaten the "one country, two systems" principle governing the semi-autonomous city, in comments following the fourth day of a strike called by pro-democracy activists which has choked the financial hub.
Hong Kong has been ruled by a unique system since its handover from British rule to China in 1997, guaranteeing greater freedoms than seen on the mainland.
But protests, which began against a now shelved extradition bill to China, have spiraled into wider calls for democracy and police accountability as worsening violence rocks the city.
For a fourth straight day on Thursday protesters caused disruption across the city with barricades and rallies, as the police drafted in reinforcements and the government denied rumors of an imminent curfew fueled by Chinese state media.
The five-month crisis entered a new phase on Monday when hardcore protesters embarked on a campaign to "blossom everywhere" across the international financial hub, in a bid to stretch police resources as thinly as possible.
The protests, fueled by fears that the territory's China-backed government is encroaching on the city's unique freedoms, are backlit by fears China may send in its troops to squash the movement.
In rare comments on the violence in Hong Kong, Xi repeated Beijing's unwavering support for the Hong Kong government and police, warning recent actions by protesters have "seriously challenged the baseline principle of 'one country, two systems'" by which it abides.
Speaking at a summit of BRICS countries in the Brazilian capital of Brasilia, he said Beijing "firmly supports" Hong Kong's government and police.
"Stopping violence and controlling chaos while restoring order is currently Hong Kong's most urgent task," Xi said in comments reported by the People's Daily.
On Thursday, Hong Kong witnessed another day of debilitating disruption, as key arterial roads were cut, many train services suspended, schools closed, while lunchtime rallies took place in the business district as protesters occupied universities.
With the protesters showing no signs of relenting, the nearly 30,000-strong city police force announced it was drafting in 100 prison guards and looking for other reinforcements.
"The ongoing riots... with their massive scale, simultaneous occurrence in various districts and grave severity of violence, make it necessary to strengthen the support for the police's front-line officers," a police spokesman said in a statement announcing the prison guards would be called in.
No other reinforcement measures were announced, although lawmaker Starry Lee, of the city's biggest pro-Beijing party, urged the government to deploy auxiliary police officers.
The part-time volunteer force of civilians and ex-officers is usually used to direct traffic and control crowds at major outdoor sports or entertainment events.
- China confusion -
While there was no suggestion in China on Thursday of the military being deployed, one of the most prominent state-run media outlets, the nationalistic Global Times, raised tensions with a report that a curfew was on the cards.
In an English post on its Twitter account, the Global Times said the Hong Kong government was looking to implement a weekend curfew, echoing unsubstantiated rumors online.
However the Global Times quickly deleted the tweet.
Hong Kong's government said the rumors were "totally unfounded".
The protest movement began in June when millions of people took to the streets voicing anger at eroding freedoms under China, which has ruled the former British colony since 1997.
Protesters are demanding the right to freely elect their leaders, as well as an independent inquiry into alleged police brutality.
Insisting it will not compromise or buckle to the pressure, China has responded with warnings it is prepared to further curb freedoms, and that it wants tougher security measures in Hong Kong.
- Fight for Freedom -
But the protesters have repeatedly shown they won't be intimidated.
Late Thursday Hong Kong fans roundly jeered the entire Chinese national anthem as the territory prepared to take on Bahrain in a World Cup qualifying match.
Earlier, office workers joined a lunchtime rally in the city's financial hub shouting "Fight for Freedom, Stand with Hong Kong", as they voiced support for the hardcore protesters on the frontlines.
"A lot of young people have been hurt," a legal worker who only gave her surname as Chan told AFP.
"They have sacrificed too much for us, so Hong Kongers must come out."
Violence has intensified from both sides this week.
The government said nearly 70 people were hospitalized on Wednesday -- two in critical condition, including a 70-year-old man hit by a brick as he tried to clear a roadblock.
In a Facebook post, police accused "rioters" of shooting "arrows at several police officers who were patrolling" near Polytechnic University, where clashes have occurred this week.
At the university, protesters bedded in overnight as they signaled they were ready for more violence, building brick walls and barricades with cement and mortar, preparing for an expected police advance.
"I’m looking forward to the police coming," said a black-clad protester who gave his name as Ah Fai.
"We're not causing the problems, the troubles stem from the government."