Chinese Hackers Suspected Of US Govt Data Breach

The White House says there is "no conclusion" on who was behind a hacking attack that may have compromised data on four million current and former US government employees.

The data breach involved the Office of Personnel Management (OPM), the human resources department for the federal government that handles security clearances and employee records.

A law enforcement official said a foreign entity or government was believed to be behind the breach, but would neither confirm nor deny media reports that China was the prime suspect.

White House spokesman Josh Earnest said on Friday there was "no conclusion" on who was behind the breach.

A spokesman for China's Foreign Ministry said: "We've seen a lot of similar reports and similar comments recently. But are they scientific?

"We say that hacking attacks have the features of being anonymous, international, and hard to trace. Without first thoroughly investigating, always saying that 'it's possible', this is irresponsible and unscientific."

The stolen data included information and background checks dating back three decades, a US official, speaking on condition of anonymity, told Reuters.

"This is deep," the official said. The data goes back to 1985.

"This means that they potentially have information about retirees, and they could know what they did after leaving government."

Employees arriving for work on Friday at the OPM were reluctant to talk to Sky News.

One man said: "I'm pretty scared, but I don't want to make a comment."

The OPM, which first detected new malicious activity affecting its information systems in April, will begin informing those whose details may have been hacked on Monday, Mr Earnest said.

:: Who's Hacking Who Right Now?

The Department of Homeland Security said it concluded at the beginning of May that the agency's data had been compromised.

The OPM said "as a result of the incident it will send notifications to approximately four million individuals".

The agency had previously been the victim of a cyberattack, as have various federal government computer systems at the State Department, the US Postal Service and the White House.

A US official who declined to be identified said the data breach could potentially affect every federal agency.

One key question is whether intelligence agency employee information was compromised.

The OPM conducts more than 90% of federal background checks, according to its website.

The FBI, which is investigating the breach, said in a statement: "The FBI is working with our interagency partners to investigate this matter.

"We take all potential threats to public and private sector systems seriously, and will continue to investigate and hold accountable those who pose a threat in cyberspace."