Google is calling on a federal judge to dismiss a lawsuit accusing it of violating privacy by electronically scanning content of emails.
Google says all users of its Gmail service must expect their emails will be subject to "automated processing."
But the lawsuit, filed in the western U.S. state of California, says the Internet giant illegally opens and reads the emails in violation of California's privacy laws and federal wiretapping statutes.
Google says it sends advertising based on words within Gmail messages, but adds no humans are reading the emails.
The case comes at a particularly sensitive time for Google after documents leaked by former U.S. intelligence analyst Edward Snowden revealed that the U.S. National Security Agency secretly gathered user data from Google and other U.S. Internet companies to track people's movements and contacts.