Tags: OPM

Data breaches at the U.S. government's personnel management agency by hackers, with suspicions centering on China, involved millions more people than previously estimated, U.S. officials said on Thursday.

The Chinese hacking group suspected of stealing sensitive information about millions of current and former U.S. government employees has a different mission and organizational structure than the military hackers who have been accused of other U.S. data breaches, according to people familiar with the matter.

The head of a U.S. agency that fell victim to cyber attacks defended its performance on Tuesday against withering criticism from lawmakers furious about a breach that compromised the personnel files of millions of federal workers.