Google has been warning it's Gmail users of potential 'state sponsored' web attacks. The search giant has been explicit in describing the attacks as state sponsored:
"We believe state-sponsored attackers may be attempting to compromise your account or computer"
This message was posted at the top of Gmail pages of users that may be at risk regardless of browser or computer type. Google has not reported how they assess which users are targeted, because they claim such information could aid such "bad actors."
The warnings hope to help guard against most likely large-scale phishing and hacking campaigns--phishing or malware. One example would be the DNSChanger malware that has inflected numerous users on both Windows PC or Mac platforms.
Above an example of the warning message.