Apple News is down for many users [update: fixed]

Update: The Apple News service appears to be fully operational once again. Original story below unchanged.
Many users are unable to use the Apple News app this morning. Rather than seeing a feed of today’s stories, upon opening the app, users are presented with an error message stating that the feed is unavailable.
If you dismiss the dialog, other areas of the News app appear still to be up. So you can browse the News+ catalog or find individual channels, but the main Today news feed