AKIPRESS.COM - China-based hackers are suspected of breaking into the computer networks of the U.S. government personnel office and stealing identifying information of at least 4 million federal workers, American officials said Thursday.

The Department of Homeland Security said in a statement that data from the Office of Personnel Management and the Interior Department had been compromised, reports AP.

"The FBI is conducting an investigation to identify how and why this occurred," the statement said.

The hackers were believed to be based in China, said Sen. Susan Collins, a Maine Republican.

Collins, a member of the Senate intelligence committee, said the breach was "yet another indication of a foreign power probing successfully and focusing on what appears to be data that would identify people with security clearances."