"This does not match with the level of ambition needed on the part of developed countries, considering their responsibilities in the challenge we face," the spokesman said in a statement to Reuters.

The 27-nation EU and the United States have been at loggerheads over curbing emissions since Bush revoked Washington's signature of the Kyoto protocol on fighting climate change shortly after taking office in 2001.

The EU introduced an Emissions Trading Scheme for carbon dioxide (CO2), the main gas blamed for global warming, and has pledged to cut its greenhouse gases by at least one-fifth by 2020 compared to 1990 levels.

"We welcome the fact that President Bush last night recognised the need for federal legislation of a legally binding nature to address greenhouse gas emissions in the United States and for the first time made a reference to cap and trade," the EU spokesman said.

"The Commission hopes that the US will reflect further on the level of ambition this represents, and notably in only stopping the growth of US emissions by 2025," he said.

The EU spokesman said developed countries needed, more than ever, to lead by example if they are to persuade major emerging countries such as China and India to join in curbing greenhouse gases to limit the rise in global temperatures.

The food crisis hitting many countries was at least partly due to extreme weather events which accelerating climate change would only aggravate, he said.