* Thousands of protesters fill Hong Kong streets
* Police largely absent as tensions subside
* People fear fresh push by police to clear crowds
* Outside world looks on with concern (Adds details, colour, British comments)
By Charlie Zhu and Donny Kwok
HONG KONG, Sept 30 (Reuters) - Tens of thousands ofpro-democracy protesters filled the streets of Hong Kong late onTuesday, stockpiling supplies and erecting makeshift barricadesahead of what some fear may be a push by police to clear theroads before Chinese National Day.
On the eve of Wednesday's anniversary of the CommunistParty's foundation of the People's Republic of China in 1949,crowds poured into central districts of the Asian financial hub,near where National Day festivities are scheduled to take place.
There was a carnival atmosphere among demonstrators, incontrast to weekend clashes when riot police fired pepper sprayand tear gas to quell the unrest.
Nevertheless, rumours have spread among protesters thatpolice could be preparing to move in again, as the pro-Beijinggovernment, which has called the demonstrations illegal, vowedto go ahead with celebrations.
"Many powerful people from the mainland will come to HongKong. The Hong Kong government won't want them to see this, sothe police must do something," Sui-ying Cheng, 18, a freshman atHong Kong University's School of Professional and ContinuingEducation, said of the National Day holiday.
"We are not scared. We will stay here tonight. Tonight isthe most important," she said.
Online student groups urged supporters to move towards theconvention centre, near the harbour waterfront, ahead of aplanned flag-raising ceremony there on Wednesday morning.
Student leaders had given Hong Kong leader Leung Chun-yingan ultimatum to come out and address the protesters beforemidnight on Tuesday, threatening to escalate action in the nextfew days to occupy more government facilities, buildings andpublic roads if he failed to do so.
The protesters, mostly students, are demanding fulldemocracy and have called on Leung to step down after Beijingruled a month ago that it would vet candidates wishing to runfor Hong Kong's leadership in 2017.
While Leung has said Beijing would not back down in the faceof protests, he also said Hong Kong police would be able tomaintain security without help from People's Liberation Army(PLA) troops from the mainland.
In a blog post published shortly before the students'deadline, Leung urged city residents to abandon the protestmovement, widely known as "Occupy Central", immediately.
"The impact on the value of Hong Kong's international imageis becoming greater and greater," he wrote. "I hope you will allthink about this."
DEMONSTRATIONS COULD ESCALATE
People voiced concern that the protests could escalate onWednesday.
"I don't know what the police or government will do to me,but I am 100 percent sure I need to come out (tonight)," saidKen To, a 35-year-old manager of a restaurant in the denselypacked Mong Kok residential district.
Its dark alleyways and triad-run bars - a far cry from theglittering high rises across the water for which Hong Kong isfamous - could prove a flashpoint for violence, residents fear,although police have steered clear of the area in recent days.
China rules Hong Kong under a "one country, two systems"formula that accords the former British colony a degree ofautonomy and freedoms not enjoyed in mainland China, withuniversal suffrage set as an eventual goal.
Protesters massed in at least four of Hong Kong's busiestareas, including Admiralty, the Central business district, thebustling shopping district of Causeway Bay and Mong Kok inKowloon.
Organisers said as many as 80,000 people thronged thestreets after demonstrations flared on Friday night, and manyhave slept out for the past four nights blocking usually busyroads. No independent estimate of crowd numbers was available.
STOCKPILING SUPPLIES
Alex Chow, leader of the Hong Kong Federation of Students,said the protests, which began as a gathering of students andthe "Occupy Central" movement, had become much broader andattracted Hong Kongers of all walks of life.
"It has evolved into a civil movement," he said.
"We can see the Beijing and Hong Kong governments alreadyfeel pressure, so the 'Occupy' movement must continue," Chowtold protesters in Admiralty.
People set up supply stations with water bottles, fruit, crackers, disposable raincoats, towels, goggles, face masks andtents, indicating they were in for the long haul.
Some lugged metal road barricades into positions on the edgeof crowds, presumably to slow a police advance. In at least onelocation, several minivans and a truck were parked in rows in anapparent effort to block a road.
"Even though I may get arrested, I will stay until the lastminute," said 16-year-old John Choi.
"We are fighting for our futures."
Protest organisers urged citizens to donate more yellowribbons, a symbol of the rallies, and goggles to protect againsttear gas and pepper spray.
Communist Party leaders in Beijing worry that calls fordemocracy could spread to the mainland, and have beenaggressively censoring news and social media comments about theHong Kong demonstrations.
The protests are the worst in Hong Kong since China resumedits rule in 1997. They also represent one of the biggestpolitical challenges for Beijing since it violently crushedpro-democracy protests in Tiananmen Square in 1989.
Cracking down too hard could shake confidence inmarket-driven Hong Kong, which has a separate legal system fromthe rest of China. Not reacting firmly enough, however, couldembolden dissidents on the mainland.
The deputy director of China's National People's CongressInternal and Judicial Affairs Committee, Li Shenming, wrote inthe People's Daily: "In today's China, engaging in an electionsystem of one-man-one-vote is bound to quickly lead to turmoil,unrest and even a situation of civil war."
FINANCIAL FALLOUT
On the financial markets, Hong Kong shares fell to athree-month low on Tuesday, registering their biggest monthlyfall since May 2012.
The city's benchmark index has plunged 7.3 percent thismonth. Chinese shares were less troubled, perhaps because newsof the protests in Hong Kong was hard to come by on themainland.
The Hong Kong Monetary Authority, the de facto central bank,said 37 branches or offices of 21 different banks had beentemporarily closed because of the protests.
Other businesses have been directly affected, includingluxury retailers in the Causeway Bay shopping mecca whereprotesters hunkered down.
The outside world has looked on warily, concerned that theclashes could spread and trigger a much harsher crackdown.
In Britain's strongest interjection yet, finance chiefGeorge Osborne urged China to seek peace and said the formercolony's prosperity depended on freedom.
Washington has urged the Hong Kong authorities "to exerciserestraint and for protesters to express their views peacefully".
The protests have also been watched closely in Taiwan, whichhas full democracy but is considered by Beijing as a renegadeprovince that must one day be reunited with the mainland.
Taiwan President Ma Ying-jeou said Beijing needed "to listencarefully to the demands of the Hong Kong people".
The United States, Australia and Singapore have issuedtravel alerts. (Additional reporting by Farah Master, Yimou Lee, ClareBaldwin, Elzio Barreto, Venus Wu, Diana Chan, James Pomfret,Kinling Lo, Twinnie Siu, Bobby Yip, Annemarie Roantree, JohnRuwitch, Irene Jay Liu and Stefanie McIntyre; Writing by PaulTait and Mike Collett-White; Editing by Mark Bendeich and JeremyLaurence)
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