Pro-democracy activist and South Horizons community organiser Joshua Wong arrives at the Southern district office as he…
FILE - Pro-democracy activist Joshua Wong arrives at the Southern district office as he requests to meet returning officer Dorothy Ma in Hong Kong, Oct. 24, 2019.

Hong Kong pro-democracy activist Joshua Wong says a decision by Hong Kong authorities to bar him from running in upcoming local elections proves "how Beijing manipulate[s] the election with political censorship and screening."

Wong posted the notice he received from an election commission officer on his Twitter page Tuesday declaring his candidacy invalid.

Wong had said last week that he was the only candidate running in the upcoming polls to be barred from taking part.

A government spokesman issued a written statement saying Wong's candidacy was invalidated because he has advocated for "self-determination" for Hong Kong.  

The 23-year-old Wong, along with fellow student activists Nathan Law and Alex Chow, stormed a courtyard on the grounds of the government's headquarters in September 2014, which led to the "Umbrella Revolution" that shut down several major highways for more than two months, demanding fully free elections.  The protests were launched after Beijing reneged on promises of universal suffrage by 2017, but ended without winning any concessions from the Hong Kong government.

The semi-autonomous city has been mired in nearly five months of massive and oftentimes violent protests since June, sparked by a proposed bill that would have allowed criminal suspects to be extradited to mainland China.  The protests have evolved into demands for full democracy for Hong Kong, along with an independent inquiry into possible use of excessive force by police and complete amnesty for all activists arrested during the demonstrations. Masked activists have vandalized businesses and the city subway system, and attacked police with bricks and homemade gasoline bombs.

Hong Kong Chief Executive Carrie Lam warned Tuesday that city's economy could see negative economic growth this year due to the protests.

Hong Kong enjoys a high degree of autonomy under the “one government, two systems” arrangement established when China regained control of the financial hub from Britain in 1997.  But political activists and observers say Beijing is slowly tightening its grip on the territory and eroding its basic freedoms.