Intelligence community sources said that the NSA is 'overwhelmed' trying to assess the damage and still doesn't know the full extent of what Snowden took with him when he worked as a former contractor at the agency.

According to NBC News, although officials, including NSA Director Keith Alexander, have assured the public that the government knows the scope of the damage, but two separate sources briefed on the matter said that the NSA has been unable to determine how many documents he took and what they are.

Edward Snowden

The sources said that the agency believes that the unreleased data includes details of data collection by US allies, including the UK, Canada, Australia and New Zealand.

They further said that the agency had poor data compartmentalization, which allowed Snowden, who was a system administrator, to roam freely across wide areas and by using a ‘thin client’ computer he remotely accessed the NSA data from his base in Hawaii.

The report added that another official said that the NSA has a poor audit capability, which is frustrating efforts to complete a damage assessment.