It also said Beijing would “enhance the system and mechanism over the appointment of the chief executive and principal officials.”

A mainland expert on Hong Kong affairs said Han would use the occasion to instruct Lam of the key policy directives laid out at the plenum meeting.

“The leadership has laid out some specific requirements and policy direction on Hong Kong. Some of these are not made public. Han will give Lam more specific directions on these points,” said the expert who spoke on condition of anonymity.

Another mainland source with government links said: “The immediate goal is still to stop the violence. A longer-term issue is to strengthen the management of civil servants. It is worrying to see government staff among protesters.”

Han is expected to relay key messages from President Xi Jinping to Lam, he said, adding it was even possible that Xi could speak to Lam directly.

There were also discussions of how to enact the national security law, also known as Article 23, as stipulated in Hong Kong’s mini-constitution the Basic Law, he said.

The city’s government originally announced on October 29 that Lam would head to Shanghai and Nanjing in a visit to end with her return to Hong Kong on Tuesday.

But Lam’s office issued a press release on Sunday morning saying she would now fly to Beijing on Tuesday night.

“[On] the next day, she will be received by the Vice-Premier of the State Council, Mr Han Zheng, in the morning, and in the afternoon, she will attend the third plenary meeting of the Leading Group for the Development of the Guangdong-Hong Kong-Macau Greater Bay Area,” the statement read.

Lam is now expected back in Hong Kong on Thursday.

The Greater Bay Area is the central government’s initiative to turn Hong Kong, Macau and nine Guangdong cities into a financial and technological powerhouse, rivalling Silicon Valley by 2035.

The last two plenary meetings of the leading group, chaired by Han, were held in August last year and March this year.

During her stay in Shanghai, Lam is set to attend the opening ceremony of the 2nd China International Import Expo, where Xi is expected to deliver the opening speech.

Carrie Lam points to protests as ‘root of problems’ as economy slumps

Hong Kong has been rocked by often-violent protests since June, triggered by the now-withdrawn extradition bill, which would have allowed for extradition to mainland China. The demonstrations have since developed into a wider anti-government movement.

Beijing so far has adopted a cautious approach on handling the city’s worst political crisis in decades, largely leaving the local government to deal with it.

But messages coming out from the plenum meeting suggest Beijing is now ready to adjust its Hong Kong policy, beyond the immediate social unrest.

One focus will be on how to better screen, manage and supervise the city’s 173,000 civil servants.

“There is no middle ground on the issue of fighting against rioters and unrest in Hong Kong. No matter whether they have given silent approval out of sympathy or connived to give support, there will be only one end to those civil servants who join the ‘black terror’. They will lose their careers and future,” the newspaper warned.

It described the behaviour of some Hong Kong government agencies as “surprisingly disappointing” and quoted the recent arrest of an assistant clerical officer from the chief secretary’s office as an example.

“At the critical juncture of curbing violence and stopping the chaos, we see some public officials have tried to obstruct the effort, some spreading pro-violence messages on social media and some even joining the rioters. Some are even serving in high positions of the SAR government’s sensitive departments and disciplined services”, it said.

“How can they continue with this misconduct while still enjoying high pay?”

Reacting to Lam’s planned trip to Beijing, pro-democracy activist Joshua Wong Chi-fung predicted she would likely be “chewed out” for the chaos in Hong Kong.

“Results of the district council elections will become a reference for Beijing to launch an inquiry, and whether to replace the chief executive,” Wong said.

Leung Che-cheung, a member of the Chinese People's Political Consultative Conference, the mainland's top advisory body, said he expected Lam to report to state leaders on Hong Kong’s latest situation, but dismissed speculation she could be asked to resign.

“From opinion polls, the chief executive certainly has more work to do. I feel the government needs to work harder and she should understand the situation better,” Leung said.

“But it’s not to the extent that she should resign. For instance, police deployment could also be improved.”

Lau Siu-kai, vice-chairman of The Chinese Association of Hong Kong and Macau Studies, a semi-official mainland think tank, believed Han would issue new directives to Lam following the conclusion of the Communist Party's plenum meeting.

“It will be the first time a state leader is meeting Lam over the political crisis. Han will likely tell her their views and tactics, asking her to cooperate,” Lau said.

Ip Kwok-him, a local deputy to the National People's Congress, China’s top legislature, agreed with Lau, saying: “Beijing has to brief the decision and principles to the relevant parties, including the Hong Kong government.”

But both Lau and Ip believed Beijing's support for Lam had not changed, despite her record low popularity.

“The movement has gone beyond her bill and targeting both Hong Kong and Beijing's authority,” Ip said. “It is not the right timing to restructure the cabinet.”

Lau also believed Lam would stay in the top post as long as she was willing to cooperate with Beijing's policies.

Additional reporting by Kimmy Chung and Alvin Lum