[HONG KONG] Tens of thousands of protesters are due to march in Hong Kong Friday to mark the anniversary of the city's handover from Britain to China, with pro-independence groups rallying for the first time amid fears Beijing is tightening its grip.
Tensions are high in the southern Chinese city after explosive revelations by a Hong Kong bookseller that he was detained and interrogated for months in mainland China after going missing last year.
Lam Wing-kee, 61, was one of five employees of a Hong Kong firm which published salacious titles about leading Chinese politicians and who disappeared only to resurface over the border.
His story fanned growing concerns that Beijing is increasing its influence in semi-autonomous Hong Kong, which is ruled under a "one country, two systems" deal enshrined in the July 1997 handover agreement, guaranteeing its freedoms and way of life for 50 years.
Mr Lam will lead the annual march on Friday.
"(Lam's case) is a very clear message to the world that China has already destroyed 'one country, two systems'," said Edward Leung of pro-independence group Hong Kong Indigenous, who will take part in a pro-independence rally planned for Friday evening.
While the main march is expected to be peaceful, the evening demonstration - to take place outside China's liaison office in protest at bookseller Lam's treatment - could be a flashpoint.
Participants say they will wear black clothes and masks. A poster advertising the rally showed mocked-up demonstrators wearing motorcycle helmets and carrying sticks.
Police have already warned they will take "resolute and effective actions against illegal acts" and say the pro-independence protesters have not asked for required permission for their rally.
Mr Leung is part of the emerging "localist" movement which grew out of disappointment that largely peaceful pro-democracy rallies in 2014 failed to win concessions.
Some activists are now demanding a return to British rule as a stepping stone towards independence, while others say violence may be necessary to force change.
Leung himself is facing charges over clashes with police in the commercial neighbourhood of Mong Kok in February.
"They (the localists) have been under some pressure (because) they haven't been able to do anything since the Mong Kok riots," said Ma Ngok, a political sciences professor at the Chinese University of Hong Kong.
"I expect them to do something dramatic." Last year's 48,000 turnout at the main march was the lowest since 2008 as fatigue set in after the 2014 protests failed to win political reform.
But organisers say they expect 100,000 people to attend Friday as frustrations have grown again.
"(Hong Kong people) are angry with the current government and very disappointed at how things are managed," said organiser Jackie Hung of the Civil Human Rights Front.
Protesters will also call for unpopular city leader Leung Chun-ying to resign after he recently hinted he may stand for a second term in 2017.
Mr Leung and his government - seen by critics as stooges of Beijing - have been slammed for failing to help the booksellers.
Mr Leung did not speak of the rally Friday morning during an official celebration of the handover, but asked Hongkongers to be "united".
"As long as we stay united and work together, Hong Kong will continue to progress and develop, and Hong Kong people will enjoy a better life and a more prosperous future," he said as a dozen protesters burned an effigy of him outside the celebration venue at the city's Convention and Exhibition Centre.