It is estimated that as many as 4 million Americans of data of civil servants have been compromised.
The Washington Post newspaper reported on Friday (5/6), hack of American computer networks by the foreign party is the largest in recent years.
This event is the second time hacking by China in less than a year. Last year Russia has also paved the White House e-mail system and the Ministry of Foreign Affairs.
Another American official who declined to be identified said the investigation currently being conducted. The hackers known to be funded by the Chinese government.
Sources close to the investigation said the Federal Bureau of Investigation (FBI) burglary suspect was carried out by hackers from China, which has also been doing a similar action in February.
The hackers who break into computer networks OPM can get information social security number, job assignments, performance assessment, and training information.
“Of course OPM into high-value targets,” said Donna Seymour, chief information officer of the OPM in an interview.