WASHINGTON, March 29 (Reuters) - A group representing major automakers on Friday urged the White House to oppose any effort by steelmaker Cleveland-Cliffs to buy rival U.S. Steel, warning that a deal could result in anti-competitive pricing for vehicles.

"A consolidation of the two companies would also place 65 to 90% of steel used in vehicles under the control of a single company," the Alliance for Automotive Innovation said in a letter seen by Reuters.

President Joe Biden said earlier this month that U.S. Steel, which has agreed to be bought by Japan's Nippon Steel, for $14.9 billion, must remain a domestically-owned U.S. firm. Cleveland-Cliffs has said it would consider another bid for U.S. Steel if the deal with Nippon Steel falls apart. (Reporting by David Shepardson; Editing by Paul Simao)