Hundreds of protesters gathered outside Hong Kong's international airport on Sunday as pro-democracy protests showed no signs of abating.

The demonstrators are determined to carry on their campaign despite increasingly violent confrontations with police and warnings from Beijing.

"Dangerous? Everyone who is out today are prepared to be arrested," said a 15-year-old protester. "But 'dangerous' is not an excuse, we should not ignore what is happening because we think it is 'dangerous' and let Hong Kong fall."

By disrupting air and train services the protesters once again focused international attention on their actions. Police said the gathering was illegal and warned of a "dispersal operation."

Appeal to Britain

Hundreds of people also massed outside the British Consulate waving British flags and chanting.

Some called for Britain to stand with them while others called for the UK to give full citizenship rights to Hong Kong citizens born before the 1997 handover of the territory to China.

The protest came after police and demonstrators clashed overnight in some of the most intense violence since the unrest started over three months ago.

Thousands gathered in Hong Kong's metro system after marching in defiance of a ban. Protesters set fire to barricades and threw petrol bombs.

Police responded with tear gas, rubber bullets and water cannon.