Down Detector showed a spike in reports of outages, with a live map showing problems across the East and West coasts of the US, as well as in the UK.
A message on the Google Apps status dashboard said:
We're investigating reports of an issue with Gmail. We will provide more information shortly.
Based on reports, it affects only Google for Work Gmail users. The users are redirected to a page with 'Service not available, contact your administrator'.
This breaking news story is being updated as more information emerges - please refresh the page for the most recent version.