Democratic groups in Hong Kong have vowed to fight a Chinese government ruling that effectively gives China control over the candidates for the next leadership election.
The election, due in 2017, will be the first in which the Hong Kong chief executive is directly chosen by voters.
However, China's legislature ruled the candidates must be approved by more than half of a special nominating body.
Angry democracy activists vowed to take over the Central business district.
Co-founder of the Occupy Central protest group, Benny Tai Yiu-ting, said: "This is the end of any dialogue. In the next few weeks, Occupy Central will start wave after wave of action.
"We will organise a full-scale act of occupying Central."
On Sunday a group of pro-democracy supporters protested in a park in front of Hong Kong government headquarters.
One protester, Henry Chung, told Agence France-Presse: "I am very sad. We have waited so many years. But now we have nothing."
Labour Party legislator Lee Cheuk-yan told the South China Morning Post there would be a "full-scale fight" against Beijing's decision.
Democratic Party chairwoman Emily Lau Wai-hing told AFP: "This is one person, one vote, but there is no choice. They have that in North Korea but you can't call it democracy."
China's ruling was approved unanimously in Beijing on Sunday afternoon by the Standing Committee of the National People's Congress (NPC).
The ruling also set out the framework for the formation of the special nominating body.
It said this would be "in accordance with" the existing 1,200-strong Election Committee - a body widely seen as dominated by pro-Beijing groups.
Analysis: BBC's Juliana Liu in Hong Kong
For many people in Hong Kong who say they want a genuine choice in the next election for chief executive, the announcement from Beijing was the worst-case scenario.
The new requirements are even tougher than the ones in the previous election, when only a committee of 1,200 electors was allowed to vote.
In 2017, candidates must gain the support of more than half of the members on a pro-Beijing nominating committee in order to be shortlisted. In 2012, only 12.5% of those votes were required.
Albert Ho, a lawmaker and the only pro-democracy candidate in the last chief executive election, told the BBC the stricter rules would rule out the possibility of another candidate like himself.
He said that pan-democratic lawmakers in the Legislative Council had vowed to vote down any proposal on electoral reform that conforms to Beijing's stated requirements.
Chief Executive Leung Chun-ying hailed the NPC decision as a "major step forward in the development of Hong Kong's society".
Li Fei, deputy secretary general of the NPC Standing Committee, said that openly nominating candidates would create a "chaotic society".
He said: "Many Hong Kong people have wasted a lot of time discussing things that are not appropriate.
"If the chief executive does not love the country and confronts Beijing, 'one country, two systems' would fail."
"One country, two systems" came into effect when Hong Kong's sovereignty reverted from the UK to China in 1997.
The Basic Law that Hong Kong adopted then allows it to retain wide legal and economic powers and civil liberties.
The Hong Kong government must still discuss Beijing's ruling and formulate a bill to be passed by Hong Kong's legislature.
If the bill is adopted under Sunday's guidelines, two to three approved candidates will contest the election.
The choice of Hong Kong's five million voters would then have to be appointed by Beijing.
China recently warned foreign countries against "meddling" in Hong Kong's politics, with an article in a state-run newspaper on Saturday accusing some in Hong Kong of "colluding" with unnamed "outside forces".
In June, almost 800,000 people in Hong Kong cast ballots in an informal referendum organised by Occupy Central on how the chief executive should be chosen.
This was followed by large-scale rallies held by both sides.
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