China warned Friday it would not tolerate any challenge to Hong Kong's governing system, as it laid out plans to boost patriotism in the city and change how its leader is chosen or removed after months of pro-democracy protests, Eurasia Diary reports citing AFP.

Beijing also said it would brook no foreign interference in Hong Kong affairs as it discussed the unrest in the semi-autonomous city at a major, four-day meeting of the Communist Party chaired by President Xi Jinping, according to a senior party cadre.

The central government in Beijing has so far voiced its confidence in Hong Kong chief executive Carrie Lam and the city police to put a lid on the increasingly violent protests.

But all eyes have been on whether the party leadership will assert more control over the situation if the demonstrations spin out of control.

The former British colony has been rocked by months of protests with citizens lampooning the city's pro-Beijing leaders and erosion of basic rights.

Shen Chunyao, director of the Hong Kong, Macau and Basic Law Commission, said party leaders at the meeting in Beijing agreed to "further improve the central government's system of governance over the region" and maintain its "long-term prosperity and stability."

China, he added, would "never tolerate any act" that aims to split the country or endanger national security.

Elements of the People's Armed Police were deployed over the summer in Shenzhen, the city bordering Hong Kong, fuelling speculation that Beijing might be prepared to intervene if necessary.

The paramilitary group was seen conducting drills with assault rifles fitted with bayonets at a sports stadium in Shenzhen on Thursday.