The PLA’s Hong Kong garrison has carried out a joint air and sea exercise in and above the city’s harbour, in a move seen as its latest attempt to send a warning to radical anti-government protesters . Warships and speedboats joined armed helicopters, infantry, special troops and other combat forces from the garrison in the joint drill. It took place on Friday, but details and video footage of the exercise were not released until Sunday, via the garrison’s official social media accounts and state broadcaster CCTV. “The patrol was a joint operation between the ground force, navy and air force focusing on emergency action, troop movements, joint operations and simulated confrontations in accordance with a coherent strategy for actual combat,” the CCTV report said. People’s Liberation Army personnel from different units had also worked together to “seize and control a wharf” in a simulated operation, according to the report. On Friday, two helicopters and four Chinese navy vessels were seen in Victoria Harbour by ferry commuters and the South China Morning Post . They included a Type 056 corvette Qinzhou, a transport vessel and two Type 074 landing boats. The PLA’s Hong Kong garrison said in a statement to the Post that it was “a routine exercise”. But military analysts said the drill aimed to send a message to radical protesters in the city, which has seen nearly seven months of unrest triggered by a now-withdrawn extradition bill . Hong Kong-based military commentator Song Zhongping said the joint exercise aimed to show that the PLA garrison was well prepared to deal with any possible “terrorist attacks” that might harm the city’s stability. Beijing officials earlier said Hong Kong was “sliding into the abyss of terrorism”, and its fears would have worsened after police seized weapons including a handgun earlier this month, according to Song. He said Beijing was also angered by the US enacting legislation in support of the protesters. “Beijing couldn’t tolerate the US intervention or the possibility of a terrorist attack happening in Hong Kong,” said Song, a military affairs commentator for Phoenix TV. “The Hong Kong garrison’s two missions are counterterrorism and defending the country’s territorial integrity, that’s why the troops have been very clearly flexing their muscles.” A video of the joint exercise aired by CCTV on Sunday showed paratroopers jumping from Z-9 helicopters onto landing boats, equipped with new helmets and rifles. Ye Weibang, deputy captain of the corvette, told the broadcaster that the drill included joint search and rescue operations, escort and capture activities. “Compared with previous drills, this one was more challenging because it was longer and involved more troops, and it was closer to being like an actual combat situation,” Ye said. It was the second bout of sabre-rattling by the PLA’s Hong Kong garrison in a week. On Christmas Eve, the state broadcaster released a video of the garrison conducting live-fire drills , led by a Qinzhou warship, in the South China Sea. Macau-based military observer Antony Wong Dong agreed that Friday’s exercise in the harbour was intended to intimidate radical protesters. But he said the South China Sea drills were more likely directed at Taiwan’s ruling, independence-leaning Democratic Progressive Party and its leader Tsai Ing-wen, who is seeking a second term at elections on January 11 . Wong also noted the Type 056 corvette’s leading role in the two exercises, saying the warship’s predecessor, the Type 037-II, had been part of missile tests during the 1995-6 Taiwan Strait crisis as Beijing sought to influence the island’s election in 1996. “The Taiwanese military controls Taiping Island [in the contested Spratly chain] – the only island with drinking water in the South China Sea,” Wong said. “So the garrison is doing something to warn Taipei, by showing its military power.” Purchase the China AI Report 2020 brought to you by SCMP Research and enjoy a 20% discount (original price US$400). This 60-page all new intelligence report gives you first-hand insights and analysis into the latest industry developments and intelligence about China AI. Get exclusive access to our webinars for continuous learning, and interact with China AI executives in live Q&A. Offer valid until 31 March 2020.