At the United Nations summit on climate change in Copenhagen, six wealthy nations have pledged 2.4 billion euros to a fund to fight deforestation - a leading source of rising temperatures.

The US, Japan, France, Great Britain, Australia and Norway said it was taking the loss of forests very seriously, which scientists say will cause droughts and storms if unchecked. In a joint statement, the six governments said they hoped the contribution for projects in the period 2010-2012 would be just the starting point for a deforestation fund by wealthy nations.

The announcement was intended to provide fresh momentum as the time is running out for delegates to seal a deal ahead of the summit's finale on Friday when an expected 119 world leaders are due in Denmark. There has been considerable disagreement at the conference between developing countries and industrial nations, which are responsible for most of the world's carbon emissions.

Europe has already pledged 7.2 billion euros towards a fund to help developing nations tackle climate change over the next three years. The US has yet to announce a contribution, although the White House has said it will offer a "fair share".

Outside, police clashed with protesters who stormed barricades around the summit venue, Copenhagen's Bella Centre. Some 260 activists, angered by the lack of progress at the summit, were detained during the clashes. The demonstrators also complained about the restrictions on access to the talks.

Climate activists in Copenhagen by Willemien Groot (RNW)