Police officers are seen in the central financial district of Hong Kong, after Beijing's decision to tightly control the nomination of candidates for Hong Kong's 2017 election, August 31, 2014. 
 
 Hong Kong Chief Executive Leung Chun-ying (C) speaks with top officers during a news conference at the Chief Executive's Office in Hong Kong August 31, 2014. 
 
 Pro-Beijing protesters take part in a rally with Chinese national flag to support Beijing in exercising decisive action outside the Chief Executive's Office in Hong Kong August 31, 2014. 
 
 A protester is seen during a campaign to kick off the Occupy Central civil disobedience event in front of the financial Central district in Hong Kong August 31, 2014. 
 
 Founders of the Occupy Central civil disobedience movement (L-R), academic Chan Kin-man, academic Benny Tai and Reverend Chu Yiu-ming attend a campaign to kick off the movement in front of the financial Central district in Hong Kong August 31, 2014. 
 
 Founders of the Occupy Central civil disobedience movement (L-R), Reverend Chu Yiu-ming, academic Benny Tai and academic Chan Kin-man, hit drums during a campaign to kick off the movement in front of the financial Central district in Hong Kong August 31, 2014. 
 
 Pro-democracy protesters hold up their mobile phones during a campaign to kick off the Occupy Central civil disobedience event in Hong Kong August 31, 2014. 
 
 A pro-democracy protester carries a placard which reads 'Communist Party, you lie!' as he sits with other protesters during a campaign to kick off the Occupy Central civil disobedience event in front of the financial Central district in Hong Kong August 31, 2014. 
 
 BEIJING/HONG KONG Pro-democracy activists vowed on Sunday to bring Hong Kong's financial hub to a standstill after China's parliament rejected their demands for the right to freely choose the former British colony's next leader in 2017. 
 
 The Standing Committee of the National People's Congress (NPC) endorsed a framework to let only two or three candidates run in the 2017 leadership vote. All candidates must first obtain majority backing from a nominating committee likely to be stacked with Beijing loyalists. 
 
 The relatively tough decision by the NPC - China's final arbiter on the city's democratic affairs - makes it almost impossible for opposition democrats to get on the ballot. 
 
 "This is a legal, fair and reasonable decision. It is a dignified, prudent decision, and its legal effect is beyond doubt," Li Fei, deputy secretary general of the NPC standing committee, told reporters after the decision. 
 
 Hundreds of "Occupy Central" activists, who demand Beijing allow a real, free election, prepared to stage a small protest late on Sunday to formally launch a campaign of civil disobedience that will climax with a blockade at some time of the city's important Central business district. 
 
 "Today is not only the darkest day in the history of Hong Kong's democratic development, today is also the darkest day of one country, two systems," said Benny Tai, a law professor and one of Occupy Central's main leaders, referring to the formula under which capitalist Hong Kong, with a population of around 7.2 million, was returned to Communist Chinese rule in 1997. 
 
 The Occupy movement said in a statement that "all chances of dialogue have been exhausted and the occupation of Central will definitely happen." It gave no timeframe for its action. 
 
 A spokesman for Hong Kong Exchanges and Clearing (0388.HK), which operates the Hong Kong Stock Exchange, said contingency planning was taken very seriously. "We have long had a specialist team that coordinates group response plans for scenarios that put at risk the continuing operation of the exchange or threaten the well-being or safety of our staff." 
 
 Hong Kong's current chief executive Leung Chun-ying said Beijing's decision represented a major step forward in Hong Kong's development. 
 
 "Universal suffrage for the (chief executive) election through "one person, one vote" by Hong Kong people is not only a big step forward for Hong Kong, but also a historic milestone for our country," he said, adding people should express their opinion through peaceful and legal methods. 
 
 Political reform has been a constant source of friction between Hong Kong's pro-democracy movement and the mainland since Britain returned the city to China 17 years ago. 
 
 In nearby Macau, another special administrative region, leader and sole candidate Fernando Chui was "re-elected" on Sunday by a select panel of 400 largely pro-China loyalists in the tiny but wealthy former Portuguese colony. 
 
 GIRDING FOR ACTION 
 
 Scores of police vehicles and hundreds of officers were deployed outside Hong Kong government headquarters as people began to gather late on Sunday, braving heavy rain at times, with some chanting slogans. 
 
 Key government buildings, including the Chief Executive's office and a People's Liberation Army barracks nearby, were also ringed by high fences and barricades. 
 
 "It (the NPC decision) leaves no room for us to fight for a genuinely democratic system, and we will begin our campaign for peaceful, non-violent struggle," said Joseph Cheng, the convener of the Alliance for True Democracy, a coalition of groups advocating universal suffrage in Hong Kong. "We want to tell the world we haven't given up. We will continue to fight." 
 
 The United States responded cautiously. Commenting on the planned protest, a U.S. official who declined to be identified by name said Washington supports Hong Kong’s "traditions and Basic Law protections of internationally recognized freedoms, including the freedom of peaceful assembly and freedom of expression." 
 
 The official also said "the legitimacy of the chief executive will be greatly enhanced if "the election provides the people of Hong Kong a genuine choice of candidates representative of the voters’ will." 
 
 "We understand that the August 31 announcement is just one step in an ongoing process leading to a final decision on election reform in Hong Kong and will continue to watch as the process unfolds," the official said in Washington. 
 
 On the surface, the NPC's decision is a breakthrough that endorses the framework for the first direct vote by a Chinese city to choose its leader. Beijing is already hailing it as a milestone in democratic reform. 
 
 However, by tightly curbing nominations for the 2017 leadership poll, some democrats said Beijing was pushing a Chinese-style version of "fake" democracy. 
 
 The NPC statement said all nominations would be carried out according to "democratic procedures" and each candidate would need the endorsement of more than half of a nominating committee that will be similar in composition to an existing 1,200-person election committee stacked with Beijing loyalists. 
 
 The proposed electoral framework will still needs to be approved by two-thirds of Hong Kong's 70-seat legislature. With pro-democracy lawmakers holding more than a third of the seats, the proposal will likely be shelved. 
 
 In that case, the next leader would likely again be chosen by a small election committee. Wang Zhenmin, a prominent legal scholar and adviser to the Chinese government, said recently that: "Less perfect universal suffrage is better than no universal suffrage," adding that this window of opportunity in Hong Kong was an historical crossroads after "2,000 years of (Chinese) feudal history without any democracy." 
 
 Senior Chinese officials have repeatedly warned activists against their "illegal" protests, and say they won't back down. 
 
 Some key members of the pro-democracy movement, including media magnate Jimmy Lai, have also come under pressure in the run-up to the Chinese parliamentary decision. 
 
 China has also repeatedly warned against foreign interference, saying it will not tolerate the use of Hong Kong "as a bridgehead to subvert and infiltrate the mainland." 
 
 The Occupy Central movement has not yet won broad support among Hong Kong's middle class, who are concerned about antagonizing China and disruptions to business. Any strong measures by China or the Hong Kong police could change that. 
 
 (Additional reporting by Pete Sweeney in SHANGHAI, Bobby Yip, Grace Li, Twinnie Siu, Dancy Zhang and Donny Kwok in HONG KONG, Lesley Wroughton and Matt Spetalnick in Washington; Editing by Paul Tait, Simon Cameron-Moore, Ian Geoghegan and Cynthia Osterman) ||||| Media playback is unsupported on your device Media caption China editor Carrie Gracie asks workers in Hong Kong's financial industry if they believe the protests will harm the economy 
 
 Tens of thousands of pro-democracy protesters are blocking Hong Kong's streets, shutting down its business hub and ignoring appeals to leave. 
 
 The demonstrations have spread to other areas including a shopping district and a residential area. 
 
 Riot police withdrew on Monday after overnight clashes in which they used batons and fired volleys of tear gas to try to disperse the crowds. 
 
 China has warned other countries not to support the "illegal rallies". 
 
 Its foreign ministry said it opposed any interference in China's internal affairs. 
 
 Meanwhile the British government called for the right to protest to be protected. 
 
 "It is important for Hong Kong to preserve these rights and for Hong Kong people to exercise them within the law," the UK foreign office said in a statement. 
 
 Protesters - a mix of students and supporters of the Occupy Central pro-democracy movement - are angry at Beijing's plans to vet candidates for Hong Kong's 2017 leadership elections. 
 
 They want a free choice of candidates when they cast their ballots for the chief executive - something Beijing says is out of the question. 
 
 Media playback is unsupported on your device Media caption "Tired yet defiant": The BBC's Laura Westbrook reports on the protesters refusing to leave 
 
 Sunday saw angry scenes and dozens of arrests on Hong Kong's streets as tens of thousands of protesters faced riot police in the heart of the city. 
 
 In a news conference on Monday, Cheung Tak-keung, assistant commissioner of police for operations, said police had used the "bare minimum force". 
 
 He said 41 people had been injured in the past three days, including 12 police officers. 
 
 The Hong Kong government urged protesters to stay calm and leave peacefully but crowds remained camped out around the government complex on Monday night. 
 
 About 3,000 people have also blocked a major road across the bay in Mongkok, on the Kowloon peninsula, while a crowd of about 1,000 faced police in the busy shopping district of Causeway Bay, east of central Hong Kong. 
 
 Image copyright AFP Image caption Protesters remained on the streets on Monday evening, with many camped outside government buildings 
 
 Image copyright Reuters Image caption About 3,000 protesters blocked a major road across the bay in Mongkok, on the Kowloon peninsula 
 
 Image copyright AP Image caption Some protesters covered their faces with plastic wrap and goggles as an anti-tear-gas measure 
 
 Image copyright Getty Images Image caption Earlier, police clashed with protesters attempting to block roads in central Hong Kong 
 
 Schools in the Wan Chai, Central and Western districts were closed on Monday and will remain shut on Tuesday, according to the Hong Kong Education Bureau. 
 
 The city remains heavily disrupted, with several major thoroughfares blocked. 
 
 One man said protesters were growing more confident. "Police don't have enough officers to close down the districts where there are protests," Ivan Yeung, 27, told AFP news agency. 
 
 Hong Kong's chief executive reassured the public that rumours the Chinese army might intervene were untrue. 
 
 "I hope the public will keep calm. Don't be misled by the rumours," CY Leung said. 
 
 China, which stations a garrison of the People's Liberation Army (PLA) in Hong Kong, said it was confident the city's administration could handle the protests. 
 
 In other developments: 
 
 Police said they used tear gas 87 times in clashes with protesters on Sunday 
 
 More than 200 bus routes have been cancelled or diverted; some subway exits in protest areas have been blocked 
 
 Several banks have suspended operations in affected areas 
 
 Police said they arrested 78 people on Sunday, after 70 arrests on Saturday. 
 
 In the Taiwanese capital, Taipei, protesters gathered outside the Hong Kong cultural office in a show of support 
 
 President Ma Ying-jeou said Taiwan was closely watching the situation in Hong Kong 
 
 In mainland China, reports say Instagram has been blocked, it is thought due to the protests 
 
 Media playback is unsupported on your device Media caption Chief Executive CY Leung said the government was "resolute in opposing the unlawful occupation" by protesters 
 
 'Sorrow over chaos' 
 
 Tensions escalated on Sunday when the broader Occupy Central protest movement threw its weight behind student-led protests, bringing forward a mass civil disobedience campaign due to start on Wednesday. 
 
 In a statement on Monday, the movement called on Mr Leung to step down, saying "only this will make it possible to re-launch the political reform process and create a space in which the crisis can be defused". 
 
 Celia Hatton: The view from Beijing 
 
 China's leaders must be sitting uncomfortably in Beijing. 
 
 As long as the protests continue, there is a chance they will spread to the mainland, where many are unhappy with one-party rule. The Chinese government is taking clear steps to limit information about events in Hong Kong by censoring internet search terms and forums discussions. 
 
 But if the protesters hold their ground, how far will Beijing allow events to spiral before getting directly involved? 
 
 The sight of Chinese troops confronting Hong Kong protesters, particularly students, would be a disaster for Beijing, leading to an international outcry. Beijing could revisit the dark days following its violent response to 1989's Tiananmen protests. 
 
 So, for now, Chinese leaders face an unusual set of political constraints. The Communist Party is unwilling to cede political control to the people of Hong Kong by refusing to allow direct elections in 2017. As a result, the party is putting its faith in the abilities of the Hong Kong police to deal with the fall-out from that decision. 
 
 A spokesman for China's Hong Kong and Macau affairs office said that Beijing firmly opposed "all illegal activities that could undermine rule of law and jeopardise 'social tranquillity,'" Xinhua news agency reports. 
 
 Mainland newspapers have blamed "radical opposition forces" for stirring up trouble. 
 
 Analysts say Communist Party leaders in Beijing are worried that calls for democracy could spread to cities on the mainland. 
 
 Britain handed Hong Kong back to China in 1997 under a "one country, two systems" formula that guarantees liberties not seen on the mainland, including freedom of speech and the right to protest. 
 
 Hong Kong democracy timeline 
 
 1997: Hong Kong, a former British colony, is handed back to China under an 1984 agreement giving it "a high degree of autonomy, except in foreign and defence affairs" for 50 years 
 
 2004: China rules that its approval must be sought for changes to Hong Kong's election laws 
 
 June-July 2014: Pro-democracy activists hold an unofficial referendum on political reform and a large rally. This is followed by protests by pro-Beijing activists 
 
 31 August 2014: China says it will allow direct elections in 2017, but voters will only be able to choose from a list of pre-approved candidates. Activists stage protests 
 
 22 September 2014: Student groups launch a week-long boycott of classes in protest 
 
 2017: Direct elections for chief executive due to take place 
 
 2047: Expiry of current agreements 
 
 Q&A: Hong Kong's democracy controversy
– Pro-democracy activists in Hong Kong have vowed to make good on their threat of widespread civil disobedience after Beijing crushed hopes of an open election for the territory's chief executive in 2017. China's legislature ruled that candidates must be backed by a nominating committee, a move that means voters are likely to have just two or three candidates to choose from—all of them nominated by a pro-Beijing committee. At a protest last night, one of the pro-democracy movement's leaders called it the "darkest day in the history of Hong Kong's democratic development" and warned that the former British colony's people "are no longer willing to be docile subjects," reports Reuters. Activists in the "Occupy Central" movement plan to paralyze Hong Kong's central business district to protest Beijing's decision. Analysts say Beijing feared that granting Hong Kong's demand for greater democracy would have led to similar demands on the mainland. "In the territory controlled by the Chinese Communist Party, only Hong Kong has some space for free speech, some judicial independence, so it is a mirror for people on the mainland," a dissident in Beijing who was placed under house arrest ahead of the government announcement tells the New York Times. "The outcome of this battle for democracy will also determine future battles for democracy for all of China." In nearby Macau, meanwhile, chief executive Fernando Chui was "re-elected" to another five-year term yesterday by a 400-strong pro-Beijing committee that didn't have any other candidates to choose from, the South China Morning Post reports. Five people were arrested last week over an informal poll on more democracy in the former Portuguese colony.