HONG Kong’s leader has said its residents are obliged to reject threats to China’s sovereignty, in what appeared to be a veiled warning aimed at rising separatist sentiment.

Chief executive Carrie Lam made the remarks in a policy speech carefully calibrated to avoid touching on politically controversial topics.

She did not specifically mention simmering tensions over the Chinese-controlled city’s burgeoning independence movement or football fans booing the national anthem.

Those issues are part of residents’ broader fears about Beijing’s tightening grip on the semi-autonomous city and erosion of its distinctive Cantonese identity.

As she spoke, a British rights activist was reportedly denied entry to Hong Kong, further underlining those concerns.

Lam, elected by a committee of mostly pro-Beijing Hong Kong elites earlier this year, said residents have “the obligation to say ‘no’ to any attempt to threaten our country’s sovereignty, security and development interests, as well as the duty to nurture our next generation into citizens with a sense of national identity”.

The Chinese central government’s recent passage of a law making it illegal to improperly use China’s national anthem, punishable by up to 15 days in prison, raised fears it could be used to undermine freedom of speech in Hong Kong.

It has become common at football games for some fans to jeer the Chinese national anthem as a way to express their unhappiness with Beijing.

At an Asian Cup qualifying match between Hong Kong and Malaysia on Tuesday night, fans raucously expressed their opposition to the anthem, with many turning their backs when March Of The Volunteers was played before the game.

Some held up a banner calling for Hong Kong independence in bold white lettering.

The new law still needs to be adopted in Hong Kong, and it is unclear how it will be implemented in the city, which has a separate legal system from the mainland.

Earlier this year Chinese president Xi Jinping warned against separatist sentiment, saying it was a “red line” that should not be crossed.