The US Government Agency that currently stores personnel information, the Office Of Personnel Management was apparently attacked by Chinese hackers. It is not known much about the attack but the attack was confirmed by officials.
The hackers were looking for personnel files for thousands of US government employees. This includes foreign contacts, jobs, intimate information, security clearances and much more. There was no affiliation reported with the Chinese government.
The reason why the personnel files were targeted seems to be that this will make future hacking attacks easier because of the personal information that is available in the databases.
This new security breach was revealed as John Kerry is currently visiting China for a bilateral meeting between Chinese and US officials. The relationship between these two countries is strained as US accused Chinese military members of hacking crimes against the US.
In the event that the latest hacking incident is true, it would be only the last in a huge list of different breaches that are carried out by different Chinese hackers against US companies and US government. The last attacks sold 2 dozen US weapon systems and broke different databases.