Nevertheless, tens of thousands of people took part in the march to the heavily guarded conference centre where world powers are struggling to hammer out a deal to combat global warming. Many rallies were being also held around the world from Australia to the Arctic Circle.

Most of the main Copenhagen rally was peaceful, but police moved in when hundreds of youths clad in black threw bricks and smashed windows.

Demonstrations were also held in Australia, Indonesia and the Philippines demanding tough measures by the 194 nations gathered at the UN Framework Convention on Climate Change(UNFCCC) conference.

The summit is due to end on Friday with a gathering of more than 110 heads of state and government to seal a deal committing major economies to curb emissions of heat-trapping fossil-fuel gases and generate hundreds of billions in dollars for poor countries badly exposed to climate change.#