BEIJING — China’s ruling Communist Party signaled it is preparing to take a tougher approach toward pro-democracy protesters in Hong Kong, declaring Friday that it would strengthen ways to “safeguard national security” and step up efforts to make Hong Kongers more patriotic toward the mainland.

The warnings, coming at the end of a four-day party meeting in which the apparatchiks reiterated their loyalty to Chairman Xi Jinping and hailed his iron-fisted leadership, mark an escalation in Beijing’s language about the protests.

“The [party’s] Central Committee seems to have reached the conclusion that they need to do more about Hong Kong and in a much more active manner,” said Jean-Pierre Cabestan, a professor of political science at Hong Kong Baptist University. “China wants to exert much more control over Hong Kong and manage the situation with a firmer grip.”

The Communist Party organs that control China conduct their business behind closed doors, providing few details about the sausage-making process of Chinese politics. This week’s meeting, officially called the Fourth Plenum of the 19th Party Congress, was no exception.

A communique released Thursday contained predictable statements about the party’s wise leadership, with Xi at its core, and the virtues of China’s socialist system. But in a news conference Friday, officials took a noticeably harder line when asked about the protests in Hong Kong, which began in June and show no sign of abating .

Beijing will act to “firmly safeguard national sovereignty and security,” said Shen Chunyao, director of the Hong Kong, Macao and Basic Law Commission. 

“We will absolutely not tolerate any behavior that challenges the bottom line of ‘one country, two systems,’ ” he told reporters, referring to the arrangement under which Hong Kong has enjoyed certain rights not available on the mainland. 

When Britain returned Hong Kong to China in 1997, Beijing agreed that the territory would enjoy a high level of autonomy for 50 years. But under Xi, that autonomy, including freedom of speech and a distinct legal system outlined in the Basic Law, the city’s de facto constitution, have been steadily eroded.

Unlike mainland China, Hong Kong has multiple political parties and a vibrant civil society. But its leader, or chief executive, must be chosen from candidates approved by Beijing and must adhere to the “one country, two systems” structure. The Communist Party and, increasingly, Hong Kong authorities will not allow any discussion of independence for the territory.

Residents of the Asian financial hub have been demonstrating against the party’s increasing encroachment into their system and are calling for the right to elect their leader without restrictions.

Hong Kong’s chief executive, Carrie Lam, is widely seen as a puppet of Beijing, while its authorities this week acted to bar democracy activist Joshua Wong, who is reviled by Beijing, from running in local elections.

In the only nod to the protesters’ concerns, Shen said that Beijing would try to “improve” the process through which Hong Kong’s chief executive was selected. However, the statement was vague and gave no details.

At Friday’s briefing, Shen also said that Beijing would not permit “any behavior encouraging separatism or endangering national security” and would keep a close watch for foreign actors “carrying out acts of separatism, subversion, infiltration and sabotage.”

This suggested that the Chinese government might encourage Hong Kong’s leaders to try to enact anti-subversion legislation, after ceding to intense public opposition on a previous attempt, or try to push through its own law from Beijing.

But that would further inflame tensions, said Suzanne Pepper, an American political analyst in Hong Kong. 

“There isn’t a whole lot that Beijing can do in that respect except issue more decisions on the Basic Law, but that will only send more people onto the streets, more violence, and harsher police measures,” she said. Still, she added, Beijing does not seem inclined to send the People’s Liberation Army onto the streets of Hong Kong. 

Despite sending unsubtle messages to Hong Kong by deploying troops to its border with the mainland, analysts say, China cannot risk heavy-handed military action — like that which brought an end to pro-democracy protests in Tiananmen Square in 1989 — in a global financial capital that helps China do business with the wider world.

 Instead, Beijing appears to want to expand its propaganda efforts, ubiquitous on the mainland, into Hong Kong. Shen said the party would increase “patriotic education” in Hong Kong “[We will]“strengthen the patriotic education of our Hong Kong and Macao compatriots, especially among civil servants and young people, teaching them about the [Chinese] constitution and the Basic Law, Chinese history and culture, in order to boost their national consciousness and patriotic spirit,” he said.

Macao is a former Portuguese colony that was handed back to China in 1999, and it operates under the same “one country, two systems” formula. Beijing has held up Macao, a gambling hub that has not been riven by protests, as an exemplary region.

 Experts scoffed at the idea that young people in cosmopolitan Hong Kong would fall for such ploys.

“Unless they put people in concentration camps like in Xinjiang, it’s not going to work,” Cabestan said, referring to reeducation camps in western China where more than 1 million Muslims have been detained. “Even if they put people in camps, it won’t work.”