As the US-China Strategic Economic Dialogue (SED) got underway in Beijing, US authorities disclosed that Chinese hackers had broken into the computer networks and databases of the US Office of Personnel Management in March this year.  The US agency houses the personal information of all federal employees including the files on tens of thousands of employees who have applied for top secret security clearances. A senior Department of Homeland Security official confirmed that the attack had occurred but said that “at this time,” neither the personnel agency nor Homeland Security had “identified any loss of personally identifiable information.” The official said an emergency response team was assigned “to assess and mitigate any risks identified.” However, one senior American official said that the attack had been traced to China.