A pro-democracy candidate has won a Hong Kong weekend by-election while a rival from a radical group who's facing riot charges placed a surprising third in a vote seen as a measure of political tension in the Chinese city.

Results released early Monday showed that Alvin Yeung of the mainstream Civic Party won the Legislative Council seat with 37 percent of the vote, edging out a pro-Beijing candidate.

But third place went to Edward Leung of Hong Kong Indigenous, who garnered 15 percent of the vote. His group is part of a fledgling movement advocating Hong Kong's independence as well as radical protest methods.

The movement has gained support amid growing unease over signs Beijing is tightening its grip on the specially administered Chinese region.