Copenhagen police battle climate protesters

The Bella Centre, where the conference is taking place, has now been shut off, with no-one allowed to enter or leave.

Activists have been angered by lack of progress on a new climate deal and also by restrictions on access to the talks.

Meanwhile, African countries have softened their demands for climate finance from rich nations.

Ethiopian Prime Minister Meles Zenawi, speaking on behalf of all African nations, announced the move, which could remove a key obstacle in the talks.

"I know my proposal today will disappoint some Africans," he said.

"My proposal scales back our expectation with respect to the level of funding in return for more reliable funding."

In another development, Danish Environment Minister Connie Hedegaard has resigned as summit president.

She will be replaced by Danish Prime Minister Lars Lokke Rasmussen.

Ms Hedegaard said the move was procedural, adding: "With so many heads of state and government having arrived, it's appropriate that the prime minister of Denmark presides."

However, behind the scenes there are said to be deep tensions between the Danish PM's office and Ms Hedegaard's department.