Ten weeks of increasingly violent clashes between police and pro-democracy protesters, angered by a perceived erosion of freedoms, are posing one of the biggest challenges for Chinese President Xi Jinping since he came to power in 2012.
Demonstrators and riot police clashed at Hong Kong's airport late on Tuesday after flights were canceled for a second day. Protesters at one point held a man who Chinese media have said was a reporter from China's Global Times newspaper.
A front-page commentary on the overseas edition of the Communist Party's official People's Daily newspaper said on Wednesday Hong Kong had reached a critical juncture.
"Using the sword of the law to stop violence and restore order is overwhelmingly the most important and urgent task for Hong Kong!" it said.
Another commentary by a Shenzhen University researcher, published by the China Daily, said the central government should deal with Hong Kong issues more decisively.
U.S. President Donald Trump said on Twitter overnight the Chinese government was moving troops to the border with Hong Kong and urged calm.
However, Chinese state media has stopped short of calling for military action to deal with the protests.
Demonstrators say they are fighting the erosion of the "one country, two systems" arrangement that enshrined some autonomy for Hong Kong after China took it back from Britain in 1997.
"Extreme political ideas have found frequent expression in Hong Kong, with some even raising 'Hong Kong independence' slogans recently. Which means the 'one country, two systems' principle faces a new challenge," Chinese author Li Peiwen said.
Chinese state media has also posted messages of support for the Hong Kong police, describing what was happening in the city as "a shame." Such posts were the most-discussed topics on China's social media platforms on Wednesday.
"We support the Hong Kong police too!" said a post on the People's Daily's official Twitter-like Weibo account that was reposted more than 500,000 times.
Global Times editor Hu Xijin said one of the newspaper's reporters was rescued by police after being tied up by demonstrators. The tabloid is published by the People's Daily.
"GT reporter Fu Guohao has been rescued by police and sent to the hospital. We're still learning about his injury conditions," said in a tweet http://bit.ly/2YW04rd.
Chinese state broadcaster CCTV called Fu "a real man" in a another Weibo post that had more than 140,000 "likes."
Netizens have been closely watching what Beijing might do next after China this week condemned some protesters for using dangerous tools to attack police and said the clashes showed "sprouts of terrorism."
The Global Times reported on Monday that China's People's Armed Police assembled in the southeastern city of Shenzhen, fueling speculation of a possible intervention in Hong Kong.Some reactions on China's social media platforms called for Beijing to intervene while many others urged calm.