Google says hackers in China have compromised the personal email accounts of hundreds of top United States officials, military personnel and journalists.
The US company said a campaign to obtain passwords originated in Jinan and was aimed at monitoring email, the BBC reports.
Google said its security was not breached, but indicated that individual users' passwords were obtained through fraud.
Chinese political activists and officials in other Asian countries were also targeted, the company said.
In Washington, the White House said it was investigating the reports, but did not believe official US government email accounts had been breached.
The email scam uses a practice known as "spear phishing", in which specific email users are tricked into divulging their log-in credentials to a web page that resembles Google's Gmail web service.
