Unclassified emails to and from President Barack Obama were read last year by Russian hackers, the New York Times reported on Saturday.
The White House confirmed the breach earlier this month, saying it took place last year and that it did not affect classified information.
The newspaper, however, said the hack “was far more intrusive and worrisome than has been publicly acknowledged”.
The president’s closely guarded BlackBerry email account was not hacked, the Times said, but communications with other users were swept up.
Quoting “senior American officials briefed on the investigation”, the Times said the hackers penetrated sensitive parts of the White House computer system, as well as the State Department. The hackers are presumed to be linked to the Russian government, if not necessarily working for it.
“It’s the Russian angle to this that’s particularly worrisome,” the Times quoted a senior official as saying.
In February, Sony was the subject of an extensive and damaging hack which Obama, in extensive and strongly worded warnings about cybersecurity, blamed on the government of North Korea.
