The White House computer system was penetrated numerous times by Chinese hackers, the Financial Times reported Friday.
The cyber attackers obtained e-mails between government officials and stole information before U.S. computer experts fixed the system, a senior U.S. official told the Financial Times.
U.S. government cyber intelligence experts suspect the attacks were sponsored by the Chinese government because of their targeted nature. They added that it is difficult to trace the exact source of an attack beyond a server in a particular country.
Newsweek magazine reported Wednesday that a foreign power hacked into the computer systems of both John McCain's and Barack Obama's presidential campaigns.
Obama's team concluded on its own that the hackers were Russian or Chinese and probably were seeking foreign policy information.
A federal law enforcement source confirmed the Newsweek story to FOX News and described the incident as "fairly significant."