Officials alert foreign services that Snowden has documents on their cooperation

WASHINGTON - U.S. officials are alerting some foreign intelligence services that documents detailing their secret cooperation with the United States have been obtained by former National Security Agency contractor Edward Snowden, according to government officials.

Snowden, U.S. officials said, took tens of thousands of documents, some of which contain sensitive material about collection programs against adversaries such as Iran, Russia, and China. Some refer to operations that in some cases involve countries not publicly allied with the United States.

The process of informing officials in capital after capital about the risk of disclosure is delicate. In some cases, one part of the cooperating government may know about the collaboration while others - such as the foreign ministry - may not, the officials said. The documents, if disclosed, could compromise operations, officials said.

The Office of the Director of National Intelligence is handling the job of informing the other intelligence services, the officials said.

In one case, for instance, the files contain information about a program run from a NATO country against Russia that provides valuable intelligence for the U.S. Air Force and Navy, said one U.S. official, who requested anonymity to discuss an ongoing criminal investigation.

"If the Russians knew about it, it wouldn't be hard for them to take appropriate measures to put a stop to it," the official said.

Snowden lifted the documents from a top secret network run by the Defense Intelligence Agency and used by intelligence arms of the Army, Air Force, Navy and Marines, according to sources, who spoke on the condition of anonymity to discuss sensitive matters.

Snowden took 30,000 documents that involve the intelligence work of one of the services, the official said. He gained access to the documents through the Joint Worldwide Intelligence Communications System, or JWICS, for top secret/sensitive compartmented information, the sources said.

The material in question does not deal with NSA surveillance but primarily with standard intelligence about other countries' military capabilities, including weapons systems - missiles, ships and jets, the officials say.

Although Snowden obtained a large volume of documents, he is not believed to have shared all of them with journalists, sources say. Moreover, he has stressed to those he has given documents that he does not want harm to result.