Officials alert foreign services that Snowden has documents on their cooperation with U.S. 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 notifications come as the Obama administration is scrambling to placate allies after allegations that the NSA has spied on foreign leaders, including German Chancellor Angela Merkel. The reports have forced the administration to play down operations targeting friends while also attempting to preserve other programs that depend on provisional partners. In either case, trust in the United States may be compromised. "It is certainly a concern, just as much as the U.S. collection [of information on European allies] being put in the news, if not more, because not only does it mean we have the potential of losing collection, but also of harming relationships," a congressional aide said. The Office of the Director of National Intelligence is handling the job of informing the other intelligence services, the officials said. ODNI declined to comment. 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. Snowden faces theft and espionage charges. "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.