By Clare Baldwin
HONG KONG (Reuters) - A top ranked Chinese official began a rare visit to Hong Kong on Tuesday vowing to listen to residents' political concerns, seeking to address increasingly strident calls in the city for greater autonomy or even independence from the mainland.
The visit by Zhang Dejiang, the first by a senior Chinese figure since the 2014 Occupy democracy protests, was officially to attend an economic summit.
However, his first comments addressed the hot button political issue of Hong Kong's relationship with China, a topic that has sparked fierce debate in the Asian financial hub.
"(I will listen to) all sectors of society's suggestions and demands on how ... the country and Hong Kong should develop," Zhang told reporters at Hong Kong airport.
Following the unsuccessful Occupy protests of 2014, a handful of activists have been calling for an outright breakaway from China, a move some say would imperil Hong Kong's economic and political future.
"These young people have no idea that they could be putting Hong Kong on a potentially dangerous collision course with the motherland and bringing an unmitigated disaster," wrote former top Hong Kong security official Regina Ip in a recent editorial in the state-run China Daily.
Tensions in the city are high, with thousands police mobilized for Zhang's visit.
Local media reported pavement bricks were being glued down to quell the prospect of violent protests while police were camping atop a mountain where a pro-democracy banner was hung two years ago.
A banner demanding "true universal suffrage" was hung on a different mountaintop on Tuesday morning.
"(We) are facing a very great threat from China: Our culture, our language, our people... we are dying!" Chan Ho-tin, the head of the newly-formed National party, told Reuters.
"Do (Hong Kong people) want to be a Chinese city or do they want to be an independent country? There are only two choices," said Chan, whose party is expected to contest legislative elections in September.
Joshua Wong, another prominent young activist who launched a new political party called Demosisto this year, wouldn't rule out taking an independence line in upcoming campaigns.
"The problem with young people is that they are not 100 percent pre-occupied with economic considerations," said Michael Tien, a Hong Kong delegate to China's parliament, the National People's Congress, which Zhang heads.
"A lot of young people saying they don't want development, they want a better environment, they want better work-life balance, they want better quality of life."
Hong Kong guarantees freedom of expression under the agreement that saw Britain return its former colony to Beijing in 1997, but authorities haven't ruled out taking action against pro-independence activists.
"Any suggestion that (Hong Kong) should be independent or any movement to advocate such independence... would be inconsistent with the legal status of Hong Kong," the Department of Justice (DOJ) told Reuters.
The DOJ said it was watching for "possible criminal activities" and would "closely monitor the situation, maintain close liaison with the relevant law enforcement agencies, and take such action as may be necessary."
Hong Kong authorities said the "counter-terrorism security measures" were needed to ensure the safety of dignitaries during the visit.
Hong Kong relies on China for vast sections of its economy, as well as much of its food, water and electricity, making independence almost impossible in practice.
China's foreign ministry said pushing for independence would harm Hong Kong's security, prosperity and stability.
"A lot of people in Hong Kong have jobs associated with the mainland," said Holden Chow, vice-chairman of the DAB party, Hong Kong's largest pro-Beijing political party.
"If there are no more economic ties... then where are the jobs? There would be a rise in unemployment."
Observers with close ties to Chinese officials say one of Zhang's priorities will be establishing relations with more moderate democrats to lower the heat.
"He will send a positive signal to any pan-democrat who is willing to have a dialogue with China," Tien said.
"This must be one of his key missions: To make sure the signal is strong enough that the electorate won't lambast the moderate pan-democrats and give all their votes to the extremists."
(Additional reporting by Stefanie McIntyre, Pak Yiu, Stella Tsang, Teenie Ho and Venus Wu; Editing by James Pomfret and Lincoln Feast)