WASHINGTON (Reuters) -A group of nine Republican state attorneys general on Friday raised competition concerns about Union Pacific's ( UNP ) UNP.N> plan to buy smaller rival Norfolk Southern ( NSC ) in an $85 billion deal to create the first U.S. coast-to-coast freight rail operator.

The officials, led by Tennessee Attorney General Jonathan Skrmetti and Kansas Attorney General Kris Kobach, in a letter to the Surface Transportation Board, which was seen by Reuters, said they were concerned the deal "will result in undue market concentration that stifles competition and therefore creates higher prices, lower reliability, and less innovation at the expense of America's manufacturers and, ultimately, America's consumers."