A White House computer network has been breached by hackers, it has been reported.
The unclassified Executive Office of the President network was attacked, according to the Washington Post.
US authorities are reported to be investigating the breach, which was reported to officials by an ally of the US, sources said.
White House officials believe the attack was state-sponsored but are not saying what - if any - data was taken.
So who is behind the White House breach? The government is keeping quiet on that front and is also refusing to comment on how much data was stolen.
However, the Washington Post indicates that the Russian government may be behind the White House breach, a theory based on recent cyberespionage campaigns carried out by Russian hackers, which are believed to be tied to the Russian government. The sources seem to agree, saying that the White House breach is similar to a "state-sponsored campaign."