A top U.S. intelligence official on Saturday declassified some details about the purpose and operations of an effort that obtains information from U.S. Internet companies as part of foreign-surveillance efforts.

James R. Clapper, director of National Intelligence, issued a statement and fact sheet to correct what he characterized as "significant misimpressions" in articles by the Washington Post and Guardian newspapers, which asserted that the government had direct access to computer systems of nine technology companies....