Three leaders of Hong Kong's democracy movement have been sentenced to jail for their roles in 2014 pro-democracy protests.

Joshua Wong, 20, Alex Chow, 24, and Nathan Law, 26, were sentenced last year to non-jail terms including community service for unlawful assembly, but Hong Kong's Department of Justice applied for a review, seeking imprisonment.

On Thursday, the appeals court jailed Wong for six months, Chow for seven months and Law for eight months.

Law had been the city's youngest democratically elected legislator before he was stripped of his seat by a government-led lawsuit in July.

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Al Jazeera's Divya Gopalan, reporting from Hong Kong, said all three of them will be taken out of politics for a considerable amount of time.

"The judge said this will serve as an example to other young activists and protesters to not break the law or conduct any violent act, so that's where their justification is to sending them to jail," she said.

Hong Kong, a former British colony, has been governed under a "one country, two systems" formula since it was returned to Chinese rule in 1997.

It was rocked by nearly three months of mostly peaceful street occupations in late 2014, demanding Beijing grant the city full democracy.

The so-called "Umbrella Movement" civil disobedience movement, which drew hundreds of thousands of protesters at its peak, was triggered after Wong and his colleagues stormed into a courtyard fronting the city's government headquarters.

They were later charged with participating in and inciting an unlawful assembly.

'No regrets'

Just before the sentencing, a defiant Wong told around 100 supporters who thronged into the High Court lobby, some weeping, that he had no regrets and urged them to keep fighting for full democracy.

"I hope Hong Kong people won't give up," said Wong.

"Victory is ours. When we are released next year, I hope we can see a Hong Kong that is full of hope. I want to see Hong Kong people not giving up. This is my last wish before I go to jail."

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In an earlier statement, the Department of Justice said the trio was not convicted for exercising their civil liberties, but because their conduct during the protest included "disorderly and intimidating behaviour".

It added there was "absolutely no basis to imply any political motive".

Hong Kong enjoys a free judiciary, unlike on the mainland where the Communist Party controls the courts which rarely challenge its decisions.

The jail terms will curtail the political ambitions of the trio, barring them from running for seats in the legislature for the next five years.

In recent months, dozens of protesters, mostly young people, have been jailed for their roles in various protests, including a violent demonstration that the government called a riot in early 2016.