The United States has accused hackers in China of accessing the private emails of top American administration officials since 2010, according to a new report.
The private emails of top US national security and trade officials have been compromised since April 2010 by Chinese hackers, NBC News reported on Monday, citing a US intelligence official and a National Security Agency (NSA) briefing in 2014.
The report said the email intrusions by Chinese hackers involved private accounts of the officials and not government email accounts which are more secure.
The report also noted that the hacking was still ongoing and that all top national security and trade officials have been targeted. The targeted officials were not publicly identified.
The Google internet company revealed in 2011 that the private Gmail accounts of some US officials had been compromised.
The cyber attacks coincide with Democratic presidential candidate Hillary Clinton's use of a private email account instead of a secure government account while she was secretary of state from 2009 to 2013.
The US has, for years, accused the Chinese government and military of conducting computer-based attacks, including efforts to steal information from federal agencies.
China has dismissed the hacking allegations as "irresponsible and unscientific."
According to a New York Times report published earlier this month, the Obama administration has decided that it must retaliate against China for the alleged theft and revelation of personal information of over 20 million Americans from government databases.
The decision came after the White House concluded that the recent hacking attack on the Office of Personnel Management (OPM) was so vast in scope that the usual practices for dealing with traditional espionage cases did not apply.