US Postal Service employee information hacked
The US Postal Service has said it was a victim of a cyber attack that may have compromised the personal information of its employees and some customers.
The agency employs more than 600,000 workers but has not specified how many people were affected.
Customers who used local post offices or the USPS website were not affected, but those who used its call centre may have had their information stolen.
The FBI is leading the investigation into the attack.
Employees' names, dates of birth, Social Security numbers and addresses may have been among the information stolen in the hack, agency spokesman David Partenheimer said.
"It is an unfortunate fact of life these days that every organisation connected to the internet is a constant target for cyber intrusion activity," Postmaster General Patrick Donahoe said in a statement.
"The United States Postal Service is no different."
Groups associated with the Chinese government are the lead suspects in the investigation, the Washington Post reports.
Such groups have been accused of hacks involving US private firms, including steel and energy companies.
The Chinese government has denied all charges of cyber theft and espionage.