The United States is warning some of its foreign intelligence counterparts that former National Security Agency contractor Edward Snowden obtained documents detailing their cooperation with the U.S., The Washington Post reported.
They could compromise operations if revealed, officials said.
Sources told the newspaper Snowden took 10s of thousands of documents from a top-secret network run by the Defense Intelligence Agency, which is used by the intelligence arm of military services.
Snowden accessed the classified information through the Joint Worldwide Intelligence Communications System. Separate from the trove of NSA surveillance information, the new documents detail standard intelligence of other countries.