Republican senator's threat to block Fed chief nominee escalates battle with Trump

By Bo Erickson, Andrea Shalal and Richard Cowan WASHINGTON, Jan 30 (Reuters) - President Donald Trump's pick of Kevin Warsh to lead the Federal Reserve is running into opposition from within his own party in Congress, as at least one Republican senator said on Friday he will block the confirmation if the Justice Department's investigation of U.S. central bank chief Jerome Powell continues.