WASHINGTON — The top U.S. intelligence official says it will take roughly five years to put in place new measures to stop another WikiLeaks-style exposure of classified information.

Director of National Intelligence Jim Clapper says officials are working to "tag" information to be able to track back to which intelligence staffers shared it - something prosecutors could have used to help prove allegations that soldier, Bradley Manning, copied thousands of war-related records that were leaked to the website Wikileaks.

Speaking to a think-tank Thursday, Clapper says the changes will also include finding ways to separate the data, such as word that a terrorist wants to hijack a flight, from how that information was collected, such as by a satellite intercept, so data can be shared among agencies without exposing their sources.