Photo: The Canadian Press

China and Kong Hong flags are displayed outside a shopping centre in Hong Kong.

Hong Kong is planning a big party as it marks 20 years under Chinese rule. But many people in the former British colony are not in the mood to celebrate.

Fireworks, a gala variety show and Chinese military displays are among the official events planned to coincide with a visit by Chinese President Xi Jinping starting Thursday for the occasion.

Ahead of the anniversary, state broadcaster China Central Television has been running daily news features extolling what it calls the inextricable ties between China and Hong Kong.

Underneath the surface, however, tensions are simmering as Hong Kongers, especially the young, chafe at life under the tightening grip of China's Communist leaders.

"People are not celebrating but worrying about Hong Kong's future and its current situation," said Nathan Law, who at age 23 was elected the city's youngest-ever lawmaker last year and was a student leader of 2014's massive "Umbrella Movement" pro-democracy demonstrations.

Members of the Demosisto political party including young activist Joshua Wong on Monday draped a giant flower statue bequeathed by Beijing in 1997 in black cloth, which they said symbolized "the hard-line rule of the authoritarian regime." 

Law said there's growing concern that Beijing is steadily eroding the "one country, two systems" principle put in place after it took control of the Asian financial hub. Under that principle, Hong Kong largely runs its own affairs and enjoys civil liberties unseen on the mainland, but now, he said, "there are lots of people describing the current system as 'one country, 1.5 systems.'"