I got this message yesterday and today. The automated voice claims that ...
"You are being contacted regarding an "enforcement action" executed by the US Treasury, intending your serious attention. Ignoring this will be an intentional second attempt to avoid initial appearance before a magistrate judge or a grand jury for a Federal criminal offense. This is the final attempt to reach you. To resolve this issue immediately and to speak to a Federal Agent call back 206-207-0173. Thank you."
My client received a similar message and asked me to call. When I did it was clearly a call center and the representative identified himself as the "Internal Revenue" with a heavy accent. When I told him I was an attorney calling on my client's behalf he hung up.