By Stefanie McIntyre and Donny Kwok
HONG KONG (Reuters) - Hong Kong residents voted in a legislative council by-election on Sunday, with a "radical" pro-democracy candidate who was arrested in a recent riot running in what is being seen as a barometer of political tensions in the financial hub.
The poll, to fill a single legislative seat vacated by a former pro-democracy politician, is being watched for signs of growing support for a burgeoning "indigenous" movement that has advocated more extreme protests, including violence, to push for greater democracy.
While candidates from across the political spectrum are competing, most attention has focused on Edward Leung, a leader of "Hong Kong Indigenous" and one of the first street activists to make a foray into mainstream politics.
"We, the young generation are determined to sacrifice ourselves for Hong Kong's future," he told Reuters on the campaign trail, flanked by supporters holding banners with the words: "Vote for a revolution".
Hong Kong, a former British colony that returned to Chinese rule in 1997 under a "one country, two systems" formula that gives it a high degree of autonomy, was rocked by massive protests in 2014 demanding Beijing's Communist Party leaders grant the city full democracy.
Beijing's refusal to give any concessions to the protesters has embittered a younger generation of activists, including Leung, who have pledged to fight on.
Some of these underlying tensions surfaced earlier this month, when hundreds of protesters clashed with police in a night-long riot. It was the worst violence seen on Hong Kong's streets for years and dozens were arrested, including Leung.
"We need to put enough pressure on the government. Therefore a kind of forceful protest is inevitable," Leung said.
Hong Kong's financial secretary, John Tsang, warned during his budget speech last week that Hong Kong risked seeing further chaos and that political uncertainty was hurting the economy.
While Leung is not expected to win, the scale of support amongst the 940,000 or so eligible voters in his constituency will be a gauge of recent anti-China sentiment, though many in the city remain strongly opposed to any radicalism.
"We need a stable environment," said a 67-year-old retired businessman, surnamed Chu, who voted for a pro-establishment candidate. "The (radicals) will add uncertainty to Hong Kong."
The results will also be an key indicator of the public mood ahead of a full legislative council poll later in the year, pitting a pro-democracy camp that now enjoys a slender one-third veto bloc against pro-Beijing and pro-establishment parties.
(Writing by James Pomfret; Editing by Alex Richardson)