British Prime Minister Tony Blair expressed hope the U.S. will sign on “at least at the beginning” of G8 efforts to adopt binding limits on carbon emissions.

His comments came after the G8 countries, plus China, India, Mexico, Brazil and South Africa, have been holding talks on emissions. Americans are in this G8 plus 5 process for the first time, Blair said.

Up to now, the Bush administration has touted voluntary agreements over binding regulation. And only last week a UN-hosted meeting ended with the US indicating it was unlikely to take part in yearend negotiations on a global agreement to cut emissions.

Washington is said to object to the targets to keep the global temperature rise below 2C this century and halve greenhouse gas emissions by 2050.