NEW YORK, May 31 (Reuters) - The United States imposing steel and aluminum tariffs on the European Union, Canada and Mexico may boost some domestic metal products, but it will likely hurt the U.S. economy, Moody's Investors Service said on Thursday. would increase input costs for a range of manufacturers, potentially feed into overall price levels and may invite retaliatory measures that hurt certain U.S. exporters,” Moody's Managing Director Atsi Sheth said in a statement.