Copenhagen negotiators struggle to save talks

Heads of state start to appear in the Danish capital later in the day, ahead of a hoped-for signing on Friday.

But several issues remain to be solved ahead of the summit's climax.

Correspondents say suspicions among poor countries that rich ones are ganging up on them - which prompted a walk-out on Monday - remain strong.

They say that with the end of the conference looming, the general hope is that minds will increasingly become concentrated and real concessions emerge from both sides.

In one hopeful sign, China has indicated it will not accept any money from a fund being set up by the West to help poorer nations tackle climate change.

A senior Chinese source told BBC News that China will not accept a single dollar.

The possibility had upset many in the United States, who feel Beijing is now well-enough off to pay to clean up its own act.

Chinese deputy foreign minister He Yafei said in Copenhagen that Beijing was committed to achieving a good outcome.

China's willingness to make a deal pleases the rich West, but alarms some poor countries, says the BBC's environment analyst Roger Harrabin.

They fear China will strike a compromise with other big players that will not be strict enough to protect the most vulnerable nations from climate change, our correspondent adds.