US trade representative Susan Schwab has said that climate change should not be used as an excuse for protectionism.
The US and EU have clashed frequently over trade issues
She was speaking in Brussels after French President Nicolas Sarkozy said a European tax could be imposed on states that refused to cap carbon emissions.
Ms Schwab said the United States had been "dismayed" at climate being used as a reason to close markets.
Speaking alongside her, EU trade commissioner Peter Mandelson agreed restrictions were not the way forward.
"They're not cost efficient, they carry a risk of retaliation, they would result in increasing cost for European industry at large," he said.
Ms Schwab also remarked on a World Trade Organisation (WTO) dispute surrounding European resistance to genetically modified organisms.
Although the United States has suspended its right to retaliate while the EU attempts to lift a ban on biotech products, she criticised attitudes in Europe.
"Using bad science to make trade policy decisions is certainly a practice that would come back to haunt all of us in other countries," she said.