WASHINGTON (Reuters) - The U.S. Treasury Department has given staff from billionaire Elon Musk's so-called Department of Government Efficiency "read only" access to its payment systems, a department official said in a letter sent to Congress.

"This is similar to the kind of access that Treasury provides to individuals reviewing Treasury systems, such as auditors, and that follows practices associated with protecting the integrity of the systems and business processes," wrote Jonathan Blum,, the department's principal deputy assistant secretary.