Millions of US government workers hit by data breach

Chinese hackers are suspected of carrying out a "massive breach" affecting the data of millions of US government workers, officials said.

The Office of Personnel Management (OPM) confirmed on Thursday that almost four million current and past employees have been affected.
The breach could potentially affect every federal agency, officials said.
Susan Collins, a member of the Senate Intelligence Committee, said the attack was thought to originate in China.
OPM serves as the human resource department for the federal government.
The agency issues security clearances and compiles records of all federal government employees.
Information stored on OPM databases include employee job assignments, performance reviews, and training, according to officials.
The breach did not involve background checks and clearance investigations, officials said.
Mrs Collins called the breach "yet another indication of a foreign power probing successfully and focusing on what appears to be data that would identify people with security clearances."
Using a new cyber security system known as Einstein, the OPM detected a "cyber-intrusion" in April 2015. The FBI said it is investigating the breach.
Ken Ammon, chief strategy officer of Xceedium - a cyber security firm - warned that the hacked data could be used to impersonate or blackmail federal employees with access to sensitive information.
Congressman Adam Schiff has called for cyber databases to be upgraded in light of the most recent attack.
Americans "expect that federal computer networks are maintained with state of the art defences", Mr Schiff said.
"The cyber threat from hackers, criminals, terrorists and state actors is one of the greatest challenges we face on a daily basis, and it's clear that a substantial improvement in our cyber databases and defences is perilously overdue."
In November 2014, a hack exposed files belonging to 25,000 employees of the Department of Homeland Security, as well as thousands of other federal employees.