Thousands of pro-democracy protesters thronged the rain-soaked streets of Hong Kong early on Wednesday, ratcheting up pressure on the pro-Beijing government that has called the action illegal and vowed to press ahead with National Day celebrations.

On the sixth day of a determined mass campaign to occupy sections of the city and express fury at a Chinese decision to limit voters' choices in a 2017 leadership election, there was little sign of momentum flagging.

That was despite widespread fears that police may use force to move crowds who have brought large sections of the Asian financial hub to a standstill and affected businesses from banks to jewellers.

Thunder, lightning and heavy rain failed to dampen spirits as protesters sought shelter under covered walkways, while police in raincoats and hats looked on passively nearby.

Demonstrators had given Hong Kong's leader an ultimatum to come out and address the crowds before midnight on Tuesday, threatening to occupy more government facilities, buildings and public roads if he failed to do so.

Hong Kong Chief Executive Leung Chun-ying had refused to do so and said Beijing would not back down in the face of protests.

The protesters then began crowding into areas near the city's waterfront Bauhinia Square, where they expected Leung to attend a flag-raising early Wednesday in honour of National Day, the anniversary of the founding of communist China in 1949.

'We are not afraid of riot police, we are not afraid of tear gas, we are not afraid of pepper spray. We will not leave until Leung Chun-ying resigns.' - Lester Shum, Hong Kong student leader

China took control of Hong Kong under an arrangement that guaranteed its 7 million people semi-autonomy, Western-style civil liberties and eventual democratic freedoms that are denied to Chinese living on the communist-ruled mainland.

The protesters want a reversal of a decision by China's government in August that a pro-Beijing panel will screen all candidates in the territory's first direct elections in 2017 — a move they view as reneging on a promise that the chief executive will be chosen through "universal suffrage."

Beijing-backed Leung's rejection of the student demands dashed hopes for a quick resolution of the standoff that has blocked city streets and forced some schools and offices to close.

It was unclear what action the demonstrators would take next. There were no immediate speeches or official statements from the protesters, who chanted "Jiayou! Jiayou!" — or "Keep it up!" — while waving their cellphones with the LED flashlights sparkling in the dark.

Both sides waiting out the standoff

As concern mounted over how the standoff might eventually end, Chinese President Xi Jinping, who has taken a hard line against any perceived threat to the Communist Party's hold on power, vowed in a National Day speech to "steadfastly safeguard" Hong Kong's prosperity and stability.

China's government has condemned the student-led protests as illegal, though so far it has not overtly intervened, leaving Hong Kong's semi-autonomous government to handle the crisis. 

HONGKONG-CHINA/

Protesters block a street in Hong Kong near an image of Chief Executive Leung Chun-ying. Hong Kong's leader says Beijing will not back down in the face of pro-democracy protests. (Carlos Barria)

Despite the hardening rhetoric from both sides, the mood Tuesday night was festive. Few police were evident, and those who were present appeared relaxed. The crowds were expected to grow, with most people off work both Wednesday and Thursday for public holidays.

Both sides appeared to be waiting out the standoff, as police continued the light-handed approach to the protests they adopted after their use of tear gas and pepper spray over the weekend failed to drive out tens of thousands of people occupying streets near the government headquarters. The sit-ins instead spread to the financial district and other areas.

The crowd had plenty of umbrellas and rain capes on hand, having stockpiled them as a defence in case police might again deploy tear gas and pepper spray.

"We are not afraid of riot police, we are not afraid of tear gas, we are not afraid of pepper spray. We will not leave until Leung Chun-ying resigns. We will not give up, we will persevere until the end," Lester Shum, another student leader, shouted to a crowd at Admiralty, near Hong Kong's waterfront.

Leung's blunt rejection of the demands from the students is not surprising. China's Communist leadership is wary of any conciliatory moves that might embolden dissidents and separatists on the mainland.

UN Secretary General Ban Ki-moon urged Tuesday that democratic principles be respected in Hong Kong.

"He understands that this is a domestic matter, but urges all stakeholders to resolve any differences in a manner that is peaceful and safeguards democratic principles," UN spokesman Stephane Dujarric told reporters.

New civil disobedience

Occupy Central, a wider civil disobedience movement, said in a tweet that the deadline set by the pro-democracy protesters includes a demand for genuine democracy and for Leung's resignation. It said it would "announce new civil disobedience plans same day," without elaborating.

HONGKONG-CHINA/

Protesters have stockpiled supplies and erected makeshift barricades ahead of Chinese National Day. (Carlos Barria/Reuters)

China took control of Hong Kong from the British in 1997 under a "one country, two systems" arrangement that guaranteed the former British colony separate legal and economic systems and Western-style civil liberties.

Hong Kong's free press and social media give the protesters exposure that may help prevent China from cracking down in the same way it has on restive minorities and dissidents living in the mainland, where public dissent is often harshly punished.

"The people on the streets are here because we've made the decision ourselves and we will only leave when we have achieved something," said Chloe Cheung, a 20-year-old student at the Hong Kong Institute of Education. "We are waiting for the government to respond to our demands for democracy and a say in what the elections will be like."

Canada's Foreign Affairs Minister John Baird is "concerned by the situation in Hong Kong and [continues] to monitor events closely," according to spokesman Adam Hodge.

"Canada reiterates its support for the implementation of universal suffrage for the election of the Chief Executive in 2017 and all members of the Legislative Council in 2020, in accordance with the Basic Law and the democratic aspirations of the Hong Kong people," Hodge said in a statement.

Grew up in prosperity

The protests have been dubbed the "Umbrella Revolution" by some because the crowds have used umbrellas to block the sun and to deflect police pepper spray.

Many of the protesters were born after an agreement with Britain in 1984 that pledged to give China control of the city of seven million, and have grown up in an era of affluence and stability, with no experience of past political turmoil in mainland China.

Their calls for a great say in their futures have widespread support among many in Hong Kong disillusioned by a widening gap between the city's ultra-wealthy tycoons and the rest of the population.

"I am committed to taking part in the protests as long as they remain peaceful," said Peter Chin, a 22-year-old student at Hong Kong University.

"We are really basically just calling for the government to speak with us but they've been mute. We'll keep staying here until they're ready to consult with us," he said.

With files from Reuters