The FBI is zeroing in on a US government office where it believes the leaked US intelligence documents on Israel’s preparations for a possible attack on Iran were printed, a US official and another source familiar with the matter told CNN.

The reports began circulating online last week, raising concerns the leaker came from within the U.S. government.

The FBI says it's investigating the unauthorized release of classified documents on Israel’s preparation for a potential retaliatory attack on Iran.

Multiple news outlets have reported the exposure of highly classified U.S. intelligence material on Israel’s potential plans for a retaliatory attack on Iran.

The FBI confirmed that the bureau is investigating the unauthorized release of top secret U.S. intelligence on Israeli preparations for a possible attack on Iran.

The FBI says it's investigating the unauthorized release of classified documents on Israel’s preparation for a potential retaliatory attack on Iran.

Top-secret documents, which surfaced on the Telegram messaging app, contain U.S. intelligence on Israel’s potential plans for a retaliatory attack on Iran.

The documents began circulating on Friday on the Telegram app, and U.S. officials are looking for the original source of the leak.

The FBI is investigating the leak of classified documents that detailed Israeli preparations to retaliate against Iran, as officials seek to clamp down on yet another embarrassing disclosure of US intelligence secrets.