The European Union is pushing Congress to support Treasury Department plans to lift sanctions on a Russian aluminum company controlled by a Vladimir Putin ally, saying the sanctions have harmed European factories.

Aluminum plants “in Austria, France, Germany, Ireland, Italy, Sweden, and the United Kingdom have faced increased prices and significant challenges in maintaining their daily operations” since the U.S. imposed sanctions last year on companies controlled by Russian businessman Oleg Deripaska, said a Jan. 4 letter signed by ambassadors from the E.U. and the named countries.

The E.U. published the letter, sent to House Speaker Nancy Pelosi and Senate Minority Leader Charles E. Schumer, on Friday, a day after House Democrats expressed concern about Treasury’s plans to lift the sanctions on Rusal and two additional companies controlled by Deripaska.

On Thursday House Democrats said Treasury Secretary Steven Mnuchin failed to convince them in a closed briefing that the United States should lift the sanctions, calling for more information and a delay.