The European Union called on the United States on Tuesday to respect EU laws after US lawmakers voted to prevent American airlines from following Europe's carbon emissions rules.
The EU will require all airlines from January 1 to buy carbon permits when they fly into and out of the 27-nation bloc, but the US House of Representatives directed the US government to stop carriers from abiding.
"We are confident that the US will respect EU law, as EU always respects US law," EU climate action commissioner Connie Hedegaard wrote on the Twitter micro-blogging website.
The US bill, which must also clear the US Senate and be signed by President Barack Obama to become law, also directs top US officials to undertake talks to ensure that US operators of civil aircraft are "held harmless" from the plan.
Hedegaard's spokesman said the EU would press ahead with its plans despite the vote in the United States.
"We do not intend to modify our adopted legislation," said the spokesman, Isaac Valero-Ladron. "The European Commission is of course open to discuss other partners' concerns on how we will implement our legislation."
US airlines are challenging the rules before the EU's Court of Justice, arguing that they violate international climate change and aviation agreements.
Explore further: NOAA: Warm oceans cause concern of coral bleaching