By Jessica Macy Yu and Yimou Lee
HONG KONG (Reuters) - About 1,000 pro-democracy activists rallied outside Hong Kong government headquarters on Monday to mark the first anniversary of protests that crippled parts of the Chinese-controlled city for weeks but failed to secure electoral reforms.
The demonstrations last year, when activists streamed on to highways to demand full democracy, became the biggest political challenge to Beijing's Communist Party leaders in years.
Police, keen to avoid any repeat of last year's occupations, far outnumbered protesters who were unable to hold a moment of silence just before 1000 GMT (6 p.m.) to recall when police fired volleys of teargas to disperse demonstrators.
Some activists accused police of disrupting their plan for the silence.
Student leader Joshua Wong told Reuters the anniversary was a time to reflect on how to make progress on the road to democracy, a sentiment echoed by Benny Tai, co-founder of the protest movement that aimed to occupy the city center.
"Our goal in the whole movement starting from Occupy Central is to awaken the general public of Hong Kong to the importance of democracy," Tai said.
"I think that has been achieved much more than expected."
The former British colony returned to Chinese rule in 1997 under a "one country, two systems" framework that gave it separate laws and an independent judiciary but reserved ultimate authority for Beijing.
The 79-day protest last year sparked what many residents of the financial hub see as a political awakening, which has included a lively debate over how much control Beijing should have.
But it failed to persuade China to allow a fully democratic vote for the city's next leader in 2017. Beijing says city voters have to chose from a list of candidates it has approved.
On Monday, many activists carried yellow umbrellas - a symbol of the fight after protesters used them to try to fend off teargas - and some held placards depicting Hong Kong's pro-Beijing leader, Leung Chun-ying, as the devil.
The mood was light-hearted although pro-Beijing groups held small gatherings nearby. The two sides traded s few insults, there was no violence.
The Umbrella Movement became the more serious unrest in the city China took it back from Britain in 1997.
Amnesty International called for the release of eight mainland Chinese activists who face long prison sentences for posting messages supporting the protests. China urged it not to interfere.
The anniversary comes after Beijing's top representative in Hong Kong suggested chief executive Leung was above the law, compounding worries about the mainland's control.
(Additional reporting by Pak Yiu, Farah Master, Venus Wu, Clare Jim, Clare Baldwin, Twinnie Siu and Diana Chan in HONG KONG, Wee Sui-Lee in BEIJING; Writing by Anne Marie Roantree; Editing by Nick Macfie, Robert Birsel)