Media playback is unsupported on your device Media caption John Sudworth: ''The students arrived at the airport accompanied by around 300 supporters''

Three pro-democracy student leaders from Hong Kong have been stopped from boarding a plane to Beijing.

They had hoped to meet China's leaders as part of their push for greater democracy, but were told at the airport that their travel permits were invalid.

Protesters have been camped out on the streets of the territory since late September.

They want Beijing to allow more candidates to stand in the territory's next leadership election in 2017.

The group were greeted at the airport by fellow democracy activists, who unfurled yellow umbrellas - a symbol of Hong Kong's democracy movement.

Image copyright EPA Image caption The group was mobbed by other protesters and the media before trying to board the flight

They were led by Alex Chow, who heads the Hong Kong Federation of Students, which has played a key role mobilising the protests

The three said they wanted to talk directly with national leaders because so far, the Hong Kong government has told them it is powerless to offer them any concessions.

A spokeswoman for the students said they were prevent from getting on the plane because their return permits had been cancelled.

Beijing has in the past blocked Hong Kong activists from travelling to mainland China.

'Naive'

The BBC's John Sudworth in China says few observers thought the student leaders had any chance of making it out of the arrival hall at Beijing airport, let alone securing a meeting with Chinese Premier Li Keqiang.

An editorial in China's state-run Global Times, written before the activists were stopped, said the group were "naive".

Hong Kong's Occupy Central movement had "failed", the editorial concluded. The protests drew tens of thousands to the streets at their peak.

A few hundred people remain at three key protest sites in organised "tent cities", complete with infrastructure such as food stalls, toilets and study areas.