The documents, according to the indictment, included details about U.S. nuclear weapons, spy satellites and the U.S. military. They were produced by the Pentagon and arms of the U.S. intelligence community, including the CIA, the National Security Agency, the National Reconnaissance Office and other agencies.

"The unauthorized disclosure of these classified documents could put at risk the national security of the United States, foreign relations, the safety of the United States military, and human sources and the continued viability of sensitive collection methods," the indictment said.

Here are some of the documents mentioned in the indictment:

- A document marked TOP SECRET//[redacted]/[redacted]//ORCON/NOFORN that the indictment says concerned "nuclear capabilities of a foreign country."

ORCON means that the material in the document cannot be disseminated outside the U.S. government department that originated it without prior approval.

- A document marked SECRET//FORMERLY RESTRICTED DATA that the indictment says concerned "nuclear weaponry of the United States."

According to a Department of Energy training guide, the Formally Restricted Data, or FRD, classification is used for materials downgraded from a higher classification that relate "primarily to the military utilization of atomic weapons."

"Formerly does not mean unclassified," says the guide.

Examples of FRD provided by the guide includes quantities of nuclear weapons in the U.S. stockpile, warhead yields and their locations.

- A document marked TOP SECRET//SI//NOFORN//FISA that the indictment says concerned "military capabilities of a foreign country and the United States, with handwritten annotation in black marker."

NOFORN means the document cannot be shared with a foreign government. FISA refers to the Foreign Intelligence Surveillance Act and means the material is from intercepted communications.

- Six top-secret documents marked TK, standing for Talent Keyhole, a classification for materials related to U.S. spy satellites.

The indictment says these documents concerned the military capabilities of foreign countries.