WASHINGTON (Reuters) - A group of 26 state attorneys general led by West Virginia and Kentucky on Wednesday challenged the Biden administration's new fuel economy rules, calling the requirements unworkable and forcing automakers to build more electric vehicles.

The National Highway Traffic Safety Administration on June 7 finalized tighter vehicle fuel economy rules through 2031 that are significantly less stringent than first proposed.

NHTSA said it would hike corporate average fuel economy (CAFE) requirements to about 50.4 miles per gallon (mpg) by 2031 from 39.1 mpg currently. The new requirement is barely above the 49 mpg it previously required for 2026.

(Reporting by David Shepardson; Editing by Chris Reese)