London, Nov 7 : Unknown foreign entity or organisation sought to gather information on policy issues of US presidential elect Barack Obama and his Republican rival John McCain by hacking their computer systems, Newsweek magazine has said.
The Telegraph quoted the magazine as saying that a federal investigation was opened after both the campaigns were victims of a sophisticated cyber attack.
"FBI and White House officials told the Obama campaign that they believed that a foreign entity or organisation sought to gather information on the evolution of both camps' policy issues - information that might be useful in negotiations with a future administration," Newsweek said.
"Obama technical experts later speculated that the hackers were Russian or Chinese," the magazine said, adding that the FBI had assured the Obama team that the attack had not been carried out by its political opponents.
Newsweek said technology experts at the Obama headquarters discovered the cyber attack in midsummer and initially thought it was a computer virus.
But the FBI and Secret Service warned them the system had been compromised and a serious amount of files had been stolen. They said the McCain campaign's computer system had been similarly compromised.
Newsweek said the Obama campaign retained a security firm following the attack and ended the intrusion.