At the height of the California energy crisis, a key computer system involved in moving electricity throughout the state was targeted by hackers, the Los Angeles Times reported Saturday.

The limited success of the hackers exposed security weaknesses in the system used by the California Independent System Operator, which oversees most of the state's electricity transmission grid, the Times said.

Officials said the problems have been corrected and there was no threat to the grid, even though the hackers came close to accessing critical parts of the system and could have disrupted the movement of power.

The Times cited an internal agency report showing the attack began as early as April 25 and wasn't detected until May 11. ISO officials said rolling blackouts May 7 and 8 were not connected to the hacking, and the FBI is investigating.

The report said the main offensive was routed through China Telecom from someone in Guangdong province in China. Hackers also apparently entered the system using Internet servers in Santa Clara and Tulsa, Okla.

"You don't know where people are really from," said James Sample, a computer security specialist at ISO. "The only reason China stuck out is because of the recent political agenda China had with the U.S. ... An ambitious U.S. hacker could have posed as a Chinese hacker."

The breach occurred amid increased tensions following the collision of a Chinese military jet and a U.S. spy plane. Following the incident, there were dozens of publicly reported computer attacks apparently originating from China. Most were minor.