In addition, more than half the agencies reported that they face challenges in trying to share information, the GAO said. For example, the Department of Homeland Security said that sensitive-but-unclassified information disseminated to state and local partners had occasionally been posted publicly online or otherwise compromised.

Finally, the GAO said most agencies do not set limits on who can designate information as sensitive but unclassified, perform periodic reviews or determine how well their practices are working, the GAO said.

'The lack of such recommended internal controls increases the risk that the designations will be misapplied,' the GAO said. 'This could result in either unnecessarily restricting materials that could be shared or inadvertently releasing materials that should be restricted.'

To provide for information-sharing policies and procedures, the GAO recommended that the Director of National Intelligence assess progress and address barriers to achieving those goals and propose changes to make them more attainable. The GAO also recommended that the director of the Office of Management and Budget (OMB), in his oversight role in terms of managing federal information, work with agencies on policies and procedures to make them more accountable.

The GAO said it requested comments on its report from the OMB director and the National Intelligence director.