HONG KONG (Reuters) - Hong Kong on Saturday banned a 21-year-old pro-democracy activist from running in a by-election in March, dealing a blow to the youth-led push for universal suffrage and prompting accusations of political interference.

Slideshow ( 5 images )

Agnes Chow, a member of the pro-democracy Demosisto party which wants self-determination for the city, had planned to run for the Hong Kong Island constituency.

“‘Self-determination’ or changing the HKSAR system by referendum which includes the choice of independence is inconsistent with the constitutional and legal status of the HKSAR as stipulated in the Basic Law,” the government said in a statement, referring to the mini-constitution.

Hong Kong is a special administrative region (SAR) of China, governed under a “one country, two systems” formula since its return from British rule in 1997, allowing freedoms not enjoyed on mainland China that include an independent judiciary but not a fully democratic vote.

“Hong Kong Demosisto has never had a pro-independence stance but we believe Hong Kong people have the right to self-determination on the future of Hong Kong,” Chow told reporters.

“Our political freedom should be well protected under the legal system of Hong Kong. The decision to disqualify my candidacy means that the political rights are being handicapped.”

Demosisto described the ban as “payback” against an entire generation.

“Demosisto members have both been imprisoned and barred from entering the political establishment. The government’s motivation is to demolish the youth’s desire to push forward social change in Hong Kong,” it said in a statement. “Momentum gained from the Umbrella movement will be absent from the legislature.”

On Tuesday, Chow’s close friend and student protest leader Joshua Wong was released on bail, less than a week after he was jailed for a second time for the Umbrella movement pro-democracy protests in 2014 that blocked the Chinese-ruled city’s major roads for months.

The protests marked the semi-autonomous city’s largest show of defiance against Beijing rule since 1997.

The by-election is one of several made necessary after the Chinese parliament issued a legal interpretation that eventually led to the debarring of six opposition lawmakers, leaving the pro-democracy camp with 24 seats in the 70-seat legislature and also effectively taking away some of its veto powers.

If Chow’s candidacy had been approved and she had gone on to win her seat, she would have been Hong Kong’s youngest ever lawmaker.