The U.S. is "deeply concerned" about the European Union's plans to impose carbon costs on some international flights, a spokesperson for the U.S. Department of ‌Transportation told Reuters on ​Monday.

"The United States remains deeply concerned about any expansion of the EU's ⁠Emission Trading System," the spokesperson said.

The ​European Commission published proposals on Friday to start ⁠applying costs on emissions from international flights departing Europe — measured by a specific point in ‌central Europe — and landing in countries ​up to 3,107 milesaway.

That threshold would exclude direct flights ‌from Europe to the U.S. — a limit some EU officials said had been designed ⁠to avoid stoking ‌tensions with ⁠President Donald Trump's administration.

However, U.S. officials are ⁠still concerned ⁠about the proposal.

"We are analyzing the European Commission's ‌proposal and will take appropriate steps as needed to protect American consumers and businesses," the spokesperson ‌added.

*Washington blocked a ‌previous attempt by the EU to expand its ETS to cover international ​flights in 2012.