The journalist who exposed classified U.S. surveillance programs leaked by an American defense contractor says there will be more 'significant revelations' to come from the documents.

Glenn Greenwald of The Guardian said Tuesday: "We are going to have a lot more significant revelations that have not yet been heard over the next several weeks and months."

Greenwald said the decision was being made on when to release the next story based on the information provided by Edward Snowden, a government contractor who some have said committed an "act of treason"

Greenwald said: "There are dozens of stories generated by the documents he provided, and we intend to pursue every last one of them."