The New York Times is reporting that the Chinese government "systematically dismantled" CIA spying operations in China starting in late 2010. The Times reports that the Chinese government killed or imprisoned at least a dozen CIA sources over the next two years.

The newspaper cites 10 current and former US officials, who describe the intelligence breach as one of the worst in decades. They spoke on condition of anonymity.

The report says US intelligence and law enforcement agencies scrambled to stem the damage, but were bitterly divided over the cause of the breach.

Some investigators were convinced there was a mole within the CIA, while others believed the Chinese had hacked the covert system the CIA used to communicate with its foreign sources.