A U.S. media outlet is reporting that Chinese hackers have been accessing the private emails of top U.S. administration officials since at least 2010.
NBC News cited a U.S. intelligence official and a top secret National Security Agency briefing, which it said Monday detailed the cyber hacking.
The official was cited as saying that the private emails of "all top national security and trade officials" were targeted, and said the email hacking is still going on.
The report said the intrusions all involved the private emails of the officials and not government email accounts which are more secure.
It said the Chinese were also able to collect the email address books of the targeted officials and used them to send malware to the officials' friends and colleagues.
Google disclosed in 2011 that the private Gmail accounts of some U.S. officials had been hacked. The NBC report says the NSA briefing shows that private email accounts from other providers were also compromised.
The time period of the hacking overlaps with Hillary Clinton's use of a private email account when she was secretary of state from 2009 to 2013. The targeted officials have not been publicly identified.