China sent fresh troops to Hong Kong on Thursday as part of an annual garrison rotation, as the financial hub braced for a 13th consecutive weekend of anti-government protests. China Central Television showed a long convoy of armoured personnel carriers and trucks crossing the Hong Kong border at night and troops in formation disembarking from a ship. State media described it as a routine rotation of the garrison stationed in the semi-autonomous financial hub. "The Hong Kong Garrison of the Chinese People's Liberation Army on Thursday morning completed the 22nd rotation since it began garrisoning Hong Kong in 1997," state news agency Xinhua news agency said. The garrison rotation this year took place after three months of anti-government demonstrations that have seen increasingly violent confrontations between mostly young protesters and the police. The unrest has prompted increasingly stern warnings from Beijing about its resolve to counter any challenge to its sovereignty over the territory. Xinhua said the newly posted troops had undergone military and legal training specific to Hong Kong. “[The troops] have grasped the ability to defend Hong Kong,” it said. The rotation came less than 24 hours after police denied permission for a mass rally planned for Saturday that was expected to draw hundreds of thousands of people to the streets. Police told the rally organisers they feared some participants would commit "violent and destructive acts". Protesters have so far carried out "arson and large-scale road blockades" and "used petrol bombs, steel balls, bricks, long spears, metal poles, as well as various self-made weapons to destroy public property", the police said in a letter the Civil Human Rights Front (CHRF). Last Sunday police deployed water cannon for the first time and an officer fire a live-round warning shot from his sidearm to fend off protesters after a sanctioned rally erupted into some of the worst violence of the past three months. CHRF leader Jimmy Sham, who said he escaped unhurt after being set upon by masked men with a baseball bat and knife earlier on Thursday, said the group would appeal against the police decision. The last rally organised by the CHRF on August 18 brought hundreds of thousands of people to the city's main public space. The protests were sparked by the city's government trying to pass a bill allowing extraditions to mainland China, but they have evolved into a wider call for greater democracy and an investigation into allegations of police brutality. Hong Kong enjoys greater freedoms than mainland China under a "one country, two systems" framework agreed before the former British territory was returned to China in 1997.